Sons of the Soil, Migrants, and Civil War by ... James D. Fearon David D. Laitin

Sons of the Soil, Migrants, and Civil War

James D. Fearon
David D. Laitin
Stanford University

1. Introduction

Ethnic diversity, if one compares countries at similar levels of economic development, is not significantly associated with a higher risk of civil war (Fearon and Laitin 2003). Even so, “ethnic” civil wars have been quite common. In most civil wars since 1945, rebel groups have explicitly advocated on behalf of an ethnic or religious group, or they have mobilized and recruited principally along the lines of an ethnic cleavage. From our list of 139 civil wars between 1945 and 2008, we code 79, or 57% as “ethnic” in this sense, and another 24 (17%) as mixed or ambiguously “ethnic.” Moreover, the prevalence of ethnic civil wars has been increasing over time. Fifty-three percent of the 17 civil wars we code as breaking out in the years 1945-49 were ethnic. For the next six decades, the corresponding percentages are 74, 71, 67, 81, 83, and 100 (for 2000-08).
These ethnic civil wars are themselves heterogeneous. A surprising number, however, exhibit a set of common features and dynamics that have been missed in the recent literature on civil war and ethnic conflict. In 32 of the civil wars in our list – about 31% of the ethnic civil wars – the spark for the war is violence between members of a regional ethnic group that considers itself to be the indigenous “sons-of-the-soil” and recent migrants from other parts of the country. The migrants are typically members of the dominant ethnic group who have come in search of land or government jobs. In many cases the state actively supports this migration with economic incentives and development schemes (occasionally funded by the World Bank or other international development agencies).
We show that these conflicts have occurred mainly in Asia and in large countries, are remarkably persistent and long-running on average, and tend to be low level in terms of fatalities. Of greater interest, we find evidence that there is a fairly common sequence of actions and reactions that produces civil wars of this sort. The violence often begins with attacks between gangs of young men from each side, or in pogroms or riots following on rumors of abuse (rapes, thefts, insults) or protests by indigenous against the migrants. State forces then intervene, often siding with the migrants, and often being indiscriminate in retribution and repression against members of the indigenous group.
In a few cases, the state intervenes on the side of the indigenous minority. Despite the intense grievances this can cause on the migrant side, escalation to civil war does not follow, because the migrants are less likely to pursue rebellion, for reasons we discuss. We also discuss factors influencing the state’s choice of whom to support, and speculate on reasons why these costly conflicts are not avoided by negotiated settlements between the state, migrants and indigenous. On the latter, we suggest that because migration will change the balance of power in the region, and because the state often cannot credibly commit to restrict migration in the future, Coasian deals that would pay off the locals or limit migration are hard to reach and implement.
Myron Weiner more than thirty years ago recognized the “potentially explosive” situation stemming from clashes between migrant and indigenous populations, in his classic Sons of the Soil. In a broader sense, it is evident that some of the worst ethnic violence in the last several centuries has involved the annihilation of indigenous groups by ethnically distinct settlers bearing “guns, germs, and steel” (Diamond 1997, Mann 2005). Nonetheless, in the recent cross-national, “micro-level,” and case study literatures on civil war, sons-of-the-soil dynamics and their frequency have been largely missed. An example is the relatively well-studied war in Sri Lanka between the Sinhalese-dominated state and the Tamil Tigers. We argue below that the standard narrative of this case misses the central importance of sons-of-the-soil dynamics in driving the escalation and maintenance of civil war violence in Sri Lanka.
In the next section, we elaborate the concept of a sons-of-the-soil conflict and present descriptive statistics and empirical patterns. In section 3 we illustrate sons-of-the-soil dynamics with a brief account of the Tamil-Sinhalese conflict. Section 4 breaks down the escalation sequence in sons-of-the-soil conflicts into several steps, and provides examples from a variety of other cases. Section 5 considers obstacles to negotiated settlements. Section 6 concludes, developing some implications of the analysis for understanding the role of grievances in explaining civil war.

2. Definitions and Empirical Patterns

A sons-of-the-soil (SoS) conflict has the following core features. First, it involves conflict between members of a minority ethnic group concentrated in some region of a country, and relatively recent, ethnically distinct migrants to this region from other parts of the same country. Second, the members of the minority group think of their group as indigenous, and as rightfully possessing the area as their group’s ancestral (or at least very long-standing) home.
By “conflict” we mean competition and dispute over scarce resources such as land, jobs, educational quotas, government services, or natural resources. A SoS conflict may be violent, but it need not be. Ideally we might like to estimate the rate at which SoS conflicts become violent, and to undertake an empirical analysis of what factors distinguish the violent cases from the non-violent ones. This would require coding ethnic groups in a sample of countries for whether they see themselves as indigenous to a particular area and whether the area is experiencing significant in-migration by another ethnic group, making for increased competition for various resources. Partly excepting some of the Minorities at Risk data discussed below, and some temporal variation within our civil war cases, we do not have such data. So we are limited here mainly to examining patterns in the set of civil wars that are driven, at least in part, by a SoS conflict.
We coded our list of 139 civil wars between 1945 and 2008 for whether they were SoS conflicts by these criteria. One “threshold” issue that needs to be specified is to say how recent the migration of the “outsiders” has to have been. Taking a view of several centuries, Catholics in Northern Ireland see themselves as sons-of-the-soil versus Protestant settlers. Serbs in Kosovo might have the same view regarding Kosovar Albanians, Africans in South Africa vis-a-vis South African whites, or Abkhaz regarding Georgians (who migrated in Abhkazia mainly in the 1920s and 30s). Although we think at least some of these cases can be profitably understood and analyzed as SoS conflicts, for our analysis here we will take “recent migration” to mean within a generation of the violent conflict’s onset.
Table 1 shows the distribution of SoS cases by region, and lists them. Thirty-one of the 139, or 22%, involve indigenous-versus-migrant conflict; as noted, this is 30% of the 103 cases of “ethnic war” in our list. Fully half of all SoS cases are in Asia, and these 16 comprise 41% of 39 civil wars we code for Asia. SubSaharan Africa is the next most common locale for SoS wars, with 26% if one counts the anti-colonial struggles in the settler colonies of Algeria, Angola, Kenya, and Mozambique.

Table 1. SoS civil wars by region.

Region Not SoS cases SoS cases All SoS cases
Asia 59%
21.3%
23 41%
51.6%
16 28.1%

39 China 1950, 1956 (Tibet), 1990 (Xinjiang); India 1956 (NE); Pakistan 1973, 2004 (Baluchistan), 1993 (MQM); Bangladesh 1976 (Chittagong); Myanmar 1948 (Karens); Sri Lanka 1983; Thailand 2004 (Pattani); Philippines 1970 (Moros); Indonesia 1965 (Papua), 1975 (E. Timor), 1989, 1999 (GAM); PNG 1989 (Bougainville).
EEur 61.5%
7.4%
8 38.5%
16.1%
5 9.4%

13 USSR 1946 (Latvia, Lithuania, Estonia); Russia 1994, 1999 (Chechnya).
LA/Ca 100%
13.9%
15 0%
0%
0 10.8%

15
NA/ME 90.5%
17.6%
19 9.5%
6.5%
2 15.1%

21 Iraq 1974 (Kurds); Israel 1949 (Palestinians).
SSA 88.9%
29.6%
32 11.1%
12.9%
4 25.9%

36 Mali 1989 (Tuaregs); Senegal 1989 (Casamance); Zimbabwe 1972; Sudan 2003 (Darfur).
West/ anticolonial wars 73.3%
10.2%
11 26.7%
12.9%
4 10.8%

15 UK/Kenya 1952 (Mau Mau); France/Algeria 1954; Portugal/Angola 1961; Portugal/Mozambique 1964.
World 77.7%
108 22.3%
31
139
Note: For the second and third columns, the entries stack the row percentage, the column percentage, and the number of cases.

Why so many SoS cases in Asia? Arguably, the physical and social geography of many Asia states are particularly conducive to this form of conflict. China, India, Bangladesh, Pakistan, Thailand, and Myanmar all have major lowland river plains densely populated by a large ethnic group that dominates the state (and usually gives it its name). The plains are often bordered by rough, much less developed mountainous terrain inhabited by diverse ethnic minorities – often “hill tribes” – who use slash-and-burn agriculture or are pastoralists. Population pressure in the river valleys can make expansion to these formerly peripheral lands attractive for poor farmers from the dominant ethnic group.
Relatedly, SoS conflicts tend to occur in larger countries, both for the set of all civil wars and just for those that have occurred in Asia. We find that SoS wars account for one of the strongest empirical regularities that has emerged from cross-national statistical studies of civil war onset, namely, that civil war is more likely in countries with larger populations (Fearon and Laitin 2003; Hegre and Sambanis 2006). If one runs an onset model (such as the one in Fearon and Laitin 2003) but coding onsets only for non-SoS conflicts, the estimated coefficient for log of country population shrinks by two thirds and is no longer statistically significant. By contrast, if one codes a dependent variable that is “1” only for SoS civil war onsets, the coefficient for population increases by about 300% and is very strongly significant. Thus, it appears that the main reason that larger population is associated with civil war onset is that larger countries have been prone to have SoS civil wars.
A striking fact about SoS conflicts is their typically long duration. They often simmer at a low level, but from the state’s perspective must seem impossible to get rid of. A simple Weibull or exponential model estimates the median duration of SoS conflicts to be about 15 years, as compared to about 7 years for all other civil wars. One quarter of all non-SoS wars are predicted to last more than 15 years, whereas one quarter of SoS conflicts are predicted to last more than 31 years. At the same time, SoS cases are much less deadly than other civil wars on average. Table 2 summarizes. All these differences would be extremely unlikely to arise by chance if in fact the distributions for SoS and non-SoS wars were the same.


Table 2. Duration and lethality of SoS versus other civil wars.

SoS civil wars Other civil wars
Estimated median duration (years)
15.1
7.1
Average killed 33,254 138,534
Median killed 11,000 20,000
Average killed/year 3,180 21,106
Median killed/year 992 3,000










Civil wars in which the rebels are seeking independence or greater autonomy for a region tend to be slightly less deadly on average than civil wars where the rebel’s goal is to capture the center. But this does not explain the differences in Table 2. SoS wars are much less lethal even within the set of autonomy-seeking civil wars.
The patterns described above use data at the level of countries and civil wars. The Minorities at Risk (MAR) project provides data at the level of groups within countries for some 342 religious and ethnic minorities in 123 countries. Groups are selected into the sample if they were judged by MAR coders to have been subject to discrimination as a group, to have organizations supporting greater group rights, or to be an “advantaged minority” subject to challenge. Unfortunately, this is not a random sample from a population of ethnic groups; MAR groups are selected based on a perception that they are at greater risk for violence or oppression. And in fact one third of MAR groups are coded as having been involved in a “small scale guerrilla activity” or greater at some time since 1945, as compared to only 15% of the 710 minority ethnic groups in Fearon’s (2003) list of ethnic groups in 166 countries.
Nonetheless, MAR has coded variables that allow us to make some comparisons at the group level concerning sons-of-the-soil and their competition with migrants. There are variables coding (a) whether the group has a regional base, (b) whether the group is indigenous and, if not, when the first wave of its members migrated to their present location, and (c) whether and to what extent the group faced “competition for vacant land” (coded for the 1980s, 1990s, and in 2000). Sharing all three characteristics should be a reasonable if imperfect coding for SoS groups facing pressure from migrants. Forty nine of the 342 MAR groups qualify, with the list including most of the groups in our Table 1, and a good number of others as well. Close to one quarter of the indigenous groups with a regional base are coded as facing competition for land in at least one decade since 1980 (49/211; but note that selection bias means that the population frequency is probably lower).

Table 3. Indigeneity, geographic concentration, land competition, and rebellion.


Migrated since 1800 or more recently “Indigenous” but not coded as facing competition for land since 1980 “Indigenous” and coded as facing competition for land since 1980
Group has no regional base 5.7%
35 10.9%
56 37.5%
8
Group has regional base 12.5%
16 30.4%
164 46.8%
49
Note: The top figure in each cell is the percentage of groups that MAR codes as having had “small guerrilla activity” or greater in at least one year since 1980. The lower figure is the number of groups in that cell.
Rates of rebellion against the state (as shown on Table 3) vary with the three factors, revealing several patterns. First, groups that have migrated to their current region more recently are much less likely to have had a rebellion against the state fought in their name. Second, groups with a regional base are more likely to have had active rebellions than groups that are dispersed throughout the country or are primarily urban. Third, indigenous groups facing “competition for vacant land” (according to MAR) have been more likely to have active rebel groups than other indigenous groups.
Based on these data, sons-of-the-soil facing competition from migrants for land appear to be particularly conflict prone – almost half have members involved in small-scale guerrilla activity or more since 1980. The results in Table 3 also suggest some possible reasons. In the first place, having a regional base, as sons-of-the-soil do, makes groups more conflict prone irrespective of whether they are indigenous to the locale. This could indicate that having a regional base favors the technology of guerrilla rebellion. Second, being indigenous (as sons-of-the-soil are) seems to make groups more conflict prone as opposed to migrants, which could indicate that they tend to have more severe grievances than migrants, or that something about their social structure or opportunities makes rebellion more feasible for them. Finally land competition is associated with higher rebellion levels among the indigenous groups whether or not they have a regional base.

3. The Sri Lanka Tamils as an Illustrative Case
To put some flesh on the abstract patterns described above, we draw on a narrative of the Tamil civil war in Sri Lanka as illustrative of SoS dynamics. Sri Lanka, with a population today of about twenty million, received independence from the UK in 1947. The two largest ethnic groups are the Sinhalese, with 74 percent of the population, and the Tamils, with 19 percent. The Tamils are divided between the Sri Lanka Tamils, those from the northeast, who see themselves as indigenous to the island (encompassing about 13 percent of the population), and the Indian Tamils, who arrived as indentured laborers to the central plantations in the nineteenth century (encompassing about 6 percent of the population).
The Sri Lankan Tamils were better educated in British schools than were the Sinhalese, and Tamils dominated both the higher civil service in the capital Colombo as well as in the business world. But the two leading political parties were dominated by Sinhalese. In 1956, amidst an economic recession, the upstart Sri Lankan Freedom Party (SLFP) defeated the old-guard United National Party (UNP) in large part by blaming the Tamils for getting the best jobs. Shortly after its victory, the new government presented parliament with the Official Language Act, which declared Sinhala the one official language. The act was passed and immediately caused a reaction among Tamils, who perceived their language, culture, and economic position to be under attack. The passage of the Official Language Act induced a satyagraha (nonviolent protest) among Tamils that was answered with violent retributions on the streets by Sinhalese. Concerned with the violence, Prime Minister S.V.R.D. Bandaranaike negotiated with S.J.V. Chelvanayakam, the leader of the Tamil-dominated Federal Party, and agreed to a wide measure of Tamil autonomy in the Northern and Eastern provinces. It also provided for the use of the Tamil language in administrative matters.
Despite the fact that it was the Tamil population that was aggrieved with policies directed at the Sinhalization of the state, much of the subsequent violent attacks were initiated by Sinhalese. Sri Lankan Tamils did not form violent militias in the 1950s and 1960s, the period in which cultural oppression intensified. Only in 1972 did Tamil groups begin violent attacks against state targets. And Tamil groups only became armed secessionists after 1977. In June 1981, local elections were held in the north to elect members of district development councils. The Tamil United Liberation Front (TULF), an umbrella party that included the Federal Party, decided to participate. Extremists within the separatist movement, however, adamantly opposed working within the existing political framework. They viewed participation in the elections as compromising the objective of a separate state. Shortly before the elections, the leading candidate of the UNP was assassinated, probably by a Tamil extremist, and this set off a stream of violence for the following three months.
Violence did not reach civil war levels until 1983 in a war pitting the Liberation Tigers of Tamil Eelam (LTTE) against the State that was precipitated by an ambush of an army patrol in the north that left thirteen Sinhalese soldiers dead. In response, savage collective retaliation occurred. The army was reputed to have killed sixty Tamil civilians in Jaffna, but most of the violence occurred in Colombo, where Sinhalese mobs destroyed Tamil shops. Sinhalese rioters in Colombo used voter lists containing home addresses to make precise attacks on the Tamil community. From Colombo, the anti-Tamil violence fanned out to the entire island. Government estimates put the death toll at 400 – mostly Tamils. Some 150,000 Tamils fled the island. Sinhalese politicians actively encouraged and may have organized pogroms, and the government of Prime Minister Jayawardene made little apparent effort to control the violence.
Civil war continued up until a precarious ceasefire brokered by the Norwegians in 2002. The war resumed in 2006, and continued until 2009, when the Sri Lankan army militarily defeated the LTTE. It has claimed the lives of at least 80,000 Sri Lankans, making it one of the longest and most brutal civil wars in the last 30 years.
Many factors help account for the Sri Lankan Tamil rebellion. Certainly the language laws built up resentment, and along with the ethnic quotas for government jobs that effectively discriminated against Tamil applicants, inducing many highly educated Tamils (those who might have been a moderating force) to emigrate to Canada, the UK and the US. The refusal of the central government to allow for cultural and legal autonomy in the Tamil region in Jaffna and the northeast was consequential in building up resentment. Also important was the role of India in providing a base of operations for Tamil insurgents in the 1980s. But a less understood element in the conditions that led to war was the sons-of-the-soil dynamic.
Sinhalese colonization of the Tamil-populated dry zone in northeastern Ceylon began in the 1930s (when still under British colonial rule) under the leadership of D. S. Senanayake, later Sri Lanka’s first Prime Minister. In 1949, the newly independent government of Sri Lanka expanded this program. It created the Gal Oya Development Board, for the purpose of settling landless peasants into this fertile area of the Eastern Province. At first, most of the migration was by Tamils and Muslims from poorer areas of the province. But then came a group of “Kandyan” Sinhalese villagers from the Central Province, and then mostly Sinhalese from other provinces. These Sinhalese received the better land (Tambiah 1996, 83-94). S. J. V. Chelvanayakam warned in his inaugural address as Federal Party leader in 1949 that the Sri Lankan government’s resettlement policy was even more dangerous to the Tamil people than the proposed Sinhala-language policy (Tambiah 1996, 83-94).
The migration of Sinhalese into the Eastern Province activated new ethnic entrepreneurs among the Tamils. The sense of demographic threat combined with the fruits of modernity being grasped by the migrants enraged the local Tamils. As Manogram (1994, 84-5) writes, the Dry Zone Tamils were “vehemently opposed to the carefully planned strategy of the government to settle Sinhalese peasants in Tamil-majority districts.” And Peebles (1990, 37-38) records that the moderate Federal party passed a resolution in 1956, claiming that the settlements were “calculated to overwhelm and crush the Tamil-speaking people in their own national areas.” So, in the aftermath of the Sinhala-only riot in Colombo in 1956 (in which there were 87 injuries but no deaths), the rioting spread to Eastern Province. In Batticaloa and Gal Oya, somewhere between 20 and 200 were killed.
Prior to that riot, when the Official Language Act was still being debated, a Tamil burned a Sinhalese shop, and the shop owner shot three Tamils who were watching the shop burn. Tamils then went to the Batticaloa-Amparai road and stoned Gal Oya Board trucks. One of the truck drivers went to Amparai and reported that a Sinhalese girl had been raped by Tamils. This rumor was sufficient to induce general assaults on Tamils. That night there were assaults by members of both groups against the other. The next day a rumor spread that a Tamil army was moving into the area, and this created a panic. By the third day, Tamil colonists in Gal Oya headed back to their home villages, and returned in large numbers with guns. In Tambiah’s reports of these riots, he notes that through it all the police force was ineffective, in large part because its members were afraid of the mobs (Tambiah 1996, 83-94).
Despite the fact that moderate Tamil leaders negotiated a compromise with the government as to who would get preference for settlement in the newly irrigated lands, under demographic challenge, Tamil-organized protest groups, parties, and self-protection (or provocation) militias began to form. In the Eastern Province, from the early periods of Sinhalese settlement, violence occurred in those divisions where Tamil-speaking people are in the majority and where Sinhalese settlements were established by the government or proposed by the government to be established. Areas that had formerly been Sinhala majority were largely free of violence. “Had the government targeted these Sinhalese-majority divisions,” Manogaran (1994, 116) argues, “rather than Tamil-majority divisions, for the establishment of Sinhalese settlements, the violence of the last two decades may have been avoided.” The threat of losing majority status in one’s homeland, he suggests, drove some Tamils into violent action. It is true that the LTTE guerrilla base became Jaffna, but the demographically mixed (and in some places tipping toward a Sinhalese majority) areas were the powder keg.
In the mixed population areas of the Eastern Province, riots, assaults and looting became the stuff of everyday life. Participating in these violent activities were Tamil irrigation workers, construction workers and truck drivers, along with IRC’s (Island Reconvicted Criminals). They might not have been directly concerned with the language issue; nor were they dispossessed of land, as these groups were relatively transient (Tambiah 1996, 83-94). These were merely violent incidents that are part of complex multiethnic space, and were complementary to the actions against settlers by outraged indigenous populations.
With the police in a precarious strategic position, unable to contain the riots, the government had to rely on its armed forces to assure security. In the late 1960s the government provocatively set up an Air Force farm at Morawewa in the Eastern Province, with a commanding position over the sea. All the Sri Lankan security forces built major camps and training academies in Trincomalee, the largest commercial center on the east coast. The historic Fort Frederick housed one major base, with another major camp and the Military Engineering College at Plantain Point. The buildings that housed the Sri Lanka Forest College at Monkey Bridge served to quarter another major camp of the Sri Lanka Army. There are smaller camps all over the district.
In assuring security to settlers in part through the visibility of the state security apparatus in the region of settlement, the government was giving license to settlers to provoke indigenous Tamils, and providing Tamils a clear set of new targets. From the time of the original Air Force farm, emboldened Sinhalese settlers and some Air Force personnel initiated small-scale attacks on local Tamils (University Teachers, 1993). K.T. Pulendran, a future leader of the Tamil Tigers, was from the east, and was affected when his village was attacked by Sinhalese colonists in 1977 when the ashes of the TULF leader S.J.V. Chelvanayakam were brought to Trincomalee.
Intimidated, the proportion of Tamils in the district population began falling. More Sinhalese were brought in under the Mahadivulweva irrigation scheme and their proportion rose to majority status in Trincomalee District, counting the near 10,000 military personnel, where they had been only a small minority a decade earlier. With the general violence in Sri Lanka of the 1980s, the gradual displacement of Tamils became a full-scale retreat. Tamil refugees escaped to the forests to the west and up north to the Jaffna peninsula, many joining rebel bands. Swamy (1994, 24) reports that in 1961 some twenty men associated with the Federal Party, disgusted at the failure of the satyagraha, created an underground group Pulip Padai (Army of Tigers) and vowed in Trincomalee (in the East) to fight for a Tamil homeland; its creators became an important seed of the future LTTE. And the rebel bands had ready targets in the state army personnel quartered in military camps.
Concern for the interests of the settlers fed government policy in a way that perpetuated the civil war. In September, 1987, violence broke out in Eastern Province where Sinhalese and Muslim settlers were protesting the provisional merger of the Northern and Eastern provinces. They recognized that because the Northern Province was overwhelmingly Tamil, a merger of the two provinces would result in their minority status. Bandaranaike's then-opposition SLFP skillfully capitalized on this atmosphere of panic, allying itself with influential Buddhist monks, who together mounted a well publicized campaign against the government's "betrayal" of the non-Tamil population of the Eastern Province, which had been growing significantly in percentage with the irrigation schemes (See Manogaran 1997 for population data). No incumbent government could survive without providing security to the settlers, which could only be assured with military participation. But military participation by definition turns vigilante action into rebellion against the state.
The Sri Lankan government continued to support Sinhala settlement in Tamil areas even though its officials understood its incendiary implications. A major reason for this is that it was popular among land-hungry southerners; a second reason is that it made sense for economic development. Thus there was an official plan in the mid-1980s to settle 30,000 Sinhalese in the dry zone of Northern Province, giving each settler land and funds to build a house and each community armed protection in the form of rifles and machine guns. Tamil spokesmen accused the government of promoting a new form of "colonialism." The government of Prime Minister Jayewardene, which was oriented mostly toward economic development and structural adjustment, denied claims to any Tamil homeland in the name of economic development of the country (Peebels, 46).
The opportunity for bands of Tamil protesters to attack army personnel, and the need for the use of army personnel to protect the migrants, however, was a formula for escalation. Tamil insurgent killing of Sri Lankan soldiers invited indiscriminate reprisals. But military actions to avenge rebel killings created new motivations for guerrilla attacks on the army. To be sure, full-scale escalation only occurred after India supported rebel groups following the 1983 riots. However, the processes of significant rebellion were hastened and sustained by the spiral of violence induced by the provocative settlement schemes, the violent incidents that could not be cauterized by the local police, the protection of settlers through the placement of military camps near the settlements, the incentives provided by the military protection for settlers to provoke the indigenous populations, and the easy targets for insurgents provided by the military stationed in local camps.

4. Common Dynamics
The features highlighted in the case of the Sri Lankan Tamils are not unique to Sri Lanka. SoS conflicts appear to have a fairly common set of escalatory dynamics and steps, as follows.
1. Migration proceeds from a relatively densely settled core to a more sparsely populated and ethnically distinct periphery, sometimes with the active support and encouragement of state policy.
2. Frictions and low-level violent clashes of various sorts arise between migrant and indigenous communities, sometimes “naturally” and sometimes with deliberate agitation of would-be communal leaders on each side.
3. The police are then called on to restore order. In poor rural areas, they often fail.
4. If the police are ineffective, the state may call in the army, choosing to side on balance with either the sons-of-the-soil or the migrants. If the state supports the indigenous, the defenseless immigrants can either return to their home areas or face uncontrolled pogroms from the locals. If the state favors the interests of the immigrants (e.g. by attacking rebels or even by remaining neutral and making sure that all residents’ security is protected), the indigenous can either accept their losses or challenge the forces of the state, who are now allied with the immigrants. In such cases, the likelihood that members of the local’s gangs (or militias) will kill soldiers is high. If this happens, the army is likely to respond with indiscriminate violence against the indigenous population, which becomes the first salvo in an escalating ethnic rebellion against the state.

Examples from other cases, step by step
1. Migration
Migrants, usually from the dominant ethnic group, settle in a new area, often encouraged by state policy intended to reduce poverty in overpopulated areas and to develop regions that are not part of the modern economy. This is typically rural-to-rural migration rather than rural-to-urban migration, and is associated with low GNP countries. In the Sindh province of Pakistan, the Partition (rather than state policy) induced massive migrations. In 1947, 95 per cent of the population was Sindhi; by 1951, 50 per cent of the urban population in Sindh was made up of Indian refugees whose mother tongue was Urdu (and called Mohajirs); this proportion reached 80 per cent in Karachi and 66 per cent in Hyderabad. Moreover, Sindhis were increasingly marginalized by Punjabi landholders who were occupying a substantial portion of the choicest lands in Sindh (Rashid and Shahhed 1993). As with the case of Gal Oya in Sri Lanka, the Punjabis, when they ruled Pakistan in alliance with the Mohajirs, funded a dam project that diverted water from the Indus away from Sindhi agricultural lands, and opened up the hinterland to migrant farmers (Tambiah 1996, 168). The Sindhis thus began to see themselves as sons-of-the-soil, demographically challenged by Mohajirs and Punjabis.
Pacified by the British in the 1820s, Assam became a center for settlers from many other Indian states, but mostly Bengal, to work in the state-sponsored tea estates. Business boomed, but labor was lacking. Not having confidence in the locals, British colonial officials trained Bengalis for administrative positions, and their descendants, educated in British schools, became the first generation of professionals in Assam, with administration run in Bengali rather than Assamese. Young Bengalis flooded Assam in search of these new middle class jobs. To make matters even worse for the indigenous population, when the Muslim League got control over the state government in 1936, it pushed hard for more immigration to assure themselves a Muslim majority (Chattopadhyay 1990, 22).
On the island of Mindanao in the Philippines, the Muslim Moros were once the majority; by 1980, they were only about 23% of the island’s population. In the colonial period, the Spanish relocated Christian Filipinos from the overcrowded and poorer islands in the north to the unpopulated frontier of Mindanao. This continued under the American administration. In 1919, the state took control over all public land, and thus Moro “ancestral land” was ceded to the state. Worse, Muslims were entitled to buy only ten hectares while Christians were permitted twenty-four. The independent Philippine government intensified this process. In 1972, 30% of the Moros had land under their name; by 1982 it was down to 17%. Many of the new landowners were Christians, as were the plantation workers in the coconut, sugar, rubber, and pineapple export sectors (Che Man 1990, 20-24). Government policies turned the Moros into sons-of-the-soil.
The Malay-Muslims of the Patani region of Thailand trace their past to a first century Malay kingdom. It was a major commercial port in the Arab/China trade, and by the end of the 12th century, it was largely Islamicized. Patani fell under Thai control in 1786. Since 1961, taking advantage of fertile land, fishing grounds, and tin, gold and other mineral deposits, 100,000 Thai-Buddhists were relocated to the Patani region and the government announced plans for yet another half million, thereby creating a new disaffected group of sons-of-the-soil (Che Man 1990, 38).
In the Chittagong Hill Tracks of today’s Bangladesh, there are some 400,000 Bengali immigrants who settled there with promises of land and money. To get this process under way, the Pakistani state built a hydro-electric project at Kaptai (funded by the US AID, begun in 1959 and completed in 1963), displacing about 100,000 tribesmen. In 1964 the special status they had during the British raj was abolished, opening the Hill tracts to outside migration without need for permit. New districts were formed, and Muslim-majority districts got disproportionate state funding. Of the 100,000 displaced hills people, 60,000 received no compensation and another 10,000 migrated to India. Those without property rights over-cultivated and eroded the hillsides. The government then tried to stimulate industry by making the Kaptai region a tax-free development zone, but the new companies looked to Bengalis for labor, leading to more migration. The Department of Fisheries denied the rights of Hill tribesmen to fish freely in the dam’s reservoir. Many of them lost all their rights to land in civil suits. Thus the Hill tribes people became, in the words of a local intellectual, “not only a minority in their own ancient homeland, but a depressed and impoverished lower stratum, often the servants of those who have taken their lands ” (Anti-Slavery Society 1984, 7, 16, 20-1, 36).
In Xinjiang Province of China, there has been since the 1950s massive immigration of Han Chinese into the Uighur regional base. Many came due to the famine associated with the Great Leap Forward, and then to escape from the excesses of the Cultural Revolution. Still others came because the state invested heavily in cotton production, in which Xinjiang has the highest yields in the country. Government actions thus encouraged massive numbers of Hans into the regional base of the Uighurs, thereby uniting them as sons-of-the-soil.

2. Frictions and Low-level Violence
The indigenous population is usually threatened by the new migrants to their region. A series of incidents, common to all complex societies but more likely when local militias have formed, raises tensions between the groups. As discussed in the Sri Lanka narrative, these incidents can be based on rumors that are elaborated with the help of alcohol.
In Assam, violent incidents between locals and immigrants were part of the warp and woof of daily life. Assamese staged processions to assert local domination that provoked violent Bengali reactions. There were assaults and counter-assaults at rallies, including the burning of imported Calcutta newspapers by Assamese student agitators. The police started shooting the protestors at Gauhati on July 1961, and killed one student. The riots continued for a month (Chattopadhyay 1990, 57-59).
Sindhis in Pakistan feared becoming minorities in their own provinces, as they were losing out in land allocation policies to Punjabi armed-forces personnel and Indian refugees. In response to this threat, a radical organization formed in 1972 called the Jiye Sind Mahaz (JSM). It sought an independent state for the Sindh, and advocated guerrilla warfare to achieve it. In 1988 Sindhi militants opened fire on Mohajirs killing more than 250, and the following day Mohajirs killed 60 Sindhis. Authorities sent in troops, and the elites from both groups signed a pact to reduce the tensions. But in July 1989 Sindhi students at the University of Karachi killed a few Mohajir student activists, and this opened up wide scale violence (Tambiah 1996, 176).
In the post-World War II Baltic States, guerrilla warfare against Soviet re-occupation began almost immediately. Much of it was organized by German collaborators who were scared that they would be killed by the Soviet occupying administration. In Estonia and Latvia, these marked men organized “forest brethren” to challenge militarily Soviet occupation, hoping for immediate western assistance (Misiunas and Taagepera 1983, 81-82). While it would be incorrect to say that the migration of Russian speakers into these republics was the mechanism that incited guerrilla activity, it would be fair to say that the facts of the migration helped the “forest brethren” gain near-universal support among the indigenous populations.
In Bangladesh, a Chittagong leaders sought, but failed to get political autonomy and a return to the British-decreed 1900 Regulation blocking settlement. Anti-tribal persecution’s, however, escalated. In response, hillsmen fled into the forests and in 1972 the Chittagong Hill Tracts Peoples Solidarity Association (PCJSS) was formed, which has acted as an unofficial local government. It has an armed wing known as Shanti Bahini (Peace Force), formed in 1972. It is lightly armed, having bought weapons in the market, as they were openly available after Bangladesh’s civil war against Pakistan (Anti Slavery Society 1984, 64). These were used to violate the security of Bengali migrants.

3. Police successfully or unsuccessfully cauterize the violence
When riots break out, the police (who tend to be drawn from the indigenous population) enter the scene. If they are able to create order, there is no escalation. But they are often poorly paid and have little interest in protecting the property of the new arrivals. Incidents will recur; in subsequent riots the police may fail.
Not in all cases do the police let matters get out of hand. In the well-known cases of Catalonia and Basque country in Spain, migrants from the dominant cultural group became a profitable work force for the indigenous industrialists. This is generally the case with rural to urban migrants in rich industrial societies. This is not to say there has been no violence between immigrants and indigenous. Rather, it is a matter of police control, which tends to be significantly stronger in richer countries.
In Kirgizia, Soviet authorities carefully investigated the spark for one riot. Local Kirghiz were stirred by (unfounded) rumors that Uzbeks had massacred all Kirgiz in one small town and were on their way to another. Many Kirgiz escaped in the mountains, causing panic. Young Kirgiz then organized to attack the homes of Uzbeks. Because of still effective Soviet police intervention, this incident, as was the case for a plethora of such incidents in the late Soviet period, was cauterized. But if Soviet authorities had defended the Uzbeks and indiscriminately attacked the Kirghiz, in an attempt to resettle Kirghizia with Uzbeks, this incident could have become the spark that set off a Kirghiz rebellion (Tishkov 1997, chap. 7).
The Thai government, also relatively strong, was initially successful in defusing unrest among the Malay-Muslims in Pattani. With independence to Malaya that did not include Pattani, many Thai Muslims moved to Malaya (where they were welcomed, and as a result pressure was taken off of Thailand); yet many others sent their children, induced by opportunities in a high growth country that welcomed assimilation, to Thai schools and took on Thai names (Che Man 1990, 163-64). Furthermore, the Thai government in the early 1980s established the Southern Border Provinces Administrative Centre. This Centre, rich with local information, rooted out officials who were provocative in their dealings with local Muslims, and established on-going relationships with Malay Muslim leaders. Amnesty and co-optation of militants (with positions offered to them in the Thai military) both worked to reduce recruitment by radical Muslims.
Under Prime Minister Thaksin, however, the managed peace was undermined. His reliance on state-supported paramilitaries (including the 70,000 strong Village Scouts) put the business of control in the hands of amateurs. He disbanded the counter-insurgency units that had excellent information on potential insurgents, accusing them of being the tools of his royalist political enemies. He gave control of counter-insurgency to the provincial police, a dumping ground for security personnel who were considered by their officers to be incompetent. With incompetent police control, a sons-of-the-soil rebellion escalated (International Crisis Group 2005).
Weaker states with poorly trained indigenous police do not easily contain interethnic violence directed against migrants. In Sri Lanka, we noted that the police were unable to contain the violence that erupted in the Eastern Province. In reference to the Assamese riots against the Marwaris in what was known as the Food Movement, the police stood by through much of this violence without acting, or dispersing the crowds (Chattopadhyay 1990). With police as the weak link in protecting the migrants, migrant communities seek protection from state militias.

4. The state decides whether to send in its army, and with which side to ally.
A. State supports the indigenous population. If the state sides with the indigenous population (giving free reign to them in their assaults on the migrants), the violence tends to remain one-sided, and the immigrant population begins a return migration (sometimes with state support) back to its overpopulated home area. In the Osh oblast of Kirgizia, when violent clashes pitted the Kirghiz against Uzbek migrants in 1990, the Soviet state supported the indigenous Kirgiz, leaving Uzbeks little choice but to lay low or migrate to Uzbekistan. Pogroms, but not civil war, were the result (Tishkov 1997, chap. 7).
In Andhra Pradesh, Prime Minister Indira Gandhi brokered a compromise between the sons-of-the-soil Telanganas and the migrant Andhras that favored the Telanganas. At first, the Indian Supreme Court disallowed protected jobs for these sons-of-the-soil. However, a series of presidential orders protected them, mostly by dividing the state into districts and requiring a high percentage of locals in each district’s educational institutions and jobs, with no sunset provision for these reservations. With these guarantees, the central state’s support for the indigenous was secure, and the Telangana movement subsided (Weiner 1978, 254). The migrant Andhras could merely accept their reduced possibilities.
In Pakistan, when Zulfiqar Ali Bhutto, a Sindhi, was elected President, Sindhi grievances on jobs and the language issue were appeased, and the share of Mohajirs in government services declined. Once the government sided with the indigenous, Sindhi violence subsided at least until Bhutto’s assassination.
There is an asymmetry in our argument that calls for an explanation: Why don’t the migrants rebel if the state sides with the indigenous? In brief, immigrant rebellions face formidable difficulties. For one, immigrants lack a rural base in which to hide from state forces, get support from noncombatants, and receive protection from neighbors who are tied together in dense social networks. As Weiner recognized, “Migrant communities, and their descendants, have a limited capacity to fight back” (1978, 135).
Second, compared to the indigenous population, migrants have a relatively cheap alternative to war: exit to their home area. As Weiner concludes, the migrants are typically more mobile than the indigenous. In cases where there is in-migration, but where the indigenous are also mobile (as in Punjab and West Bengal), there is no evidence of nativism (Weiner 1978, 278). Mobile populations, he infers, do not rebel. Even while the Bangladeshi government was supporting the settlers in the Chittagong Hills, as the army distributed weapons to the settlers, many of the settlers were oriented toward a “return” if things got dangerous. The Shanti Bahini give “quit” notices to settlers, and if they agreed to evacuate, they were promised safe passage. In 1981 some 2,000 Bengalis returned this way (Mey 1984, 133).
Third, for urban trading groups, where there are strong social networks that cross borders, exit is especially easy. In regard to challenges from “sons-of-the-soil,” Weiner speculates (1978, 135), “the Marwaris and other business communities may choose to invest elsewhere.”
B. State sides with the migrants. By contrast, if the state sides with the immigrants – which is likely if the migrants are of the same ethnic group as or in political alliance with the state leadership -- the indigenous population can either give in to state power (in which case there is uneasy peace, going back to low grade communal violence), or escalate violence. If the indigenous group militias begin to attack the state army (which are typically staffed by soldiers who share ethnicity with the migrants), we often find the army responding with indiscriminate killing of locals, due to lack of information as to who is a rebel. In 1980 in the Chittagong Hill Tracts, the Shanti Bahini decimated an army patrol protecting thousands of newly arrived Bengali settlers streaming into the hills. Subsequently the army, in cahoots with these Bengali settlers, massacred 300 hillsmen. The army commander then requested tribal leaders to attend a meeting to restore law and order at the Buddhist temple. Once all were gathered, the army opened fire killing all the attending hillsmen. Encouraged by state support, settlers attacked tribal families, burning houses, and destroying temples. The indiscriminate response by settlers (who formed “home guards” to assure that Bengali property was not threatened), and supported by state armies, set off a rebellious spiral (Anti Slavery Society 1984, 55ff.; for fuller documentation, see Amnesty International 1986, 13-23).
In Assam, local police harassed Bengalis with the threat of taking away citizenship papers in the late 1970s, and Assamese agitators began to terrorize those who they considered as foreigners, especially the tea garden laborers. India’s Central Reserve Police entered the fray on the side of the immigrants. In the course of their peace keeping (i.e. ending the pogroms against the immigrants) they killed an Assamese agitator, turning him into a martyr. Assamese militants then attacked minority communities. By early 1980, in a massacre aided and abetted by the Assam’s police, local people killed about 200 Bengali immigrants inaugurating a war that accounted for 7,000 deaths by 1985 (Chattopadhyay, 1990, 81-83).
The Philippine Constabulary at the height of Moro insurrection in the 1970s gave its support to the “Ilaga terrorist squads” that fought against the Moros. The Armed Forces of the Philippines joined on the same side after martial law was declared in 1972, and large scale conventional military campaigns followed until 1976 with the signing of the Tripoli agreement, which established Autonomous Governments in the region. The Moros could set up Shar'ia Courts, got the right to tax, and could retain their own Special Security Forces. But a series of presidential decrees circumscribed the autonomy, and the insurgency persisted (Che Man 1990, 149). The alliance between the militias of the migrants and the forces of the state turned communal warfare into rebellion.
In Xinjiang, the militarized Xinjiang Production and Construction Corps, made up of demobilized soldiers from the People’s Liberation Army, former Guomindang soldiers and armed Han settlers has been responsible to deter disturbances against the Han settlers. These officers provide easy targets for Uighur separatists. In the spring of 1996, Uighur insurgents opened fire on police officers in several cities. Because these were officers, the killings were immediately coded as rebellion. The government responded with searches of people’s homes seeking out separatist sympathizers, and official state sources spoke of a “steel wall” to protect the stability of the province (Dillon 1997, 80-86). Yet Uighurs were still able to wage an insurgency, as was illustrated graphically in an attack on a police convoy on the eve of the August 2008 Olympic Games, and the subsequent riots with increasing deaths in 2009.
In Bougainvillea, an Australian-based company set up shop to mine copper in the early 1970s. Local villagers, who received almost no royalties, noticed that the once-rich Jaba River was turning into liquid mud. Fish disappeared. Local rebels began killing provincial officials. The Papua/New Guinea government supported the company and its migrant workforce. The Papuan Defense Forces began to shell the rebels into submission. In response, the rebels consolidated as the Bougainvillea Revolutionary Army and confronted the Papuan armed forces (Hyndman 1994). Although limited migration makes this borderline as an SoS case, we again see the entry of the state army to protect migrants and their property turning local battles into a civil war.
Mixed population rural areas are not immune from ethnic violence, but without in-migration by dominant group settlers, the violence tends not to implicate the state and thus remains at low levels. We note that in the MAR data set there are thirty-six indigenous groups that have not been in significant rebellion against the state since 1980, yet have seen high levels of “communal conflict” with neighboring groups (that is, a MAR communal conflict coding of either “communal rioting” or “communal warfare” since 1980). This set includes several groups in central and western Kenya, the Xhosas and Zulus in South Africa, the Northern Ireland Catholics in the UK, and the indigenous populations of Colombia and Peru. Communal conflicts between indigenous groups in the countryside may be resolved by mechanisms that have been in place before the emergence of a centralized state apparatus (Fearon and Laitin 1996). The state often has no interest in getting drawn into these conflicts, and thus can mediate or suppress them more effectively.
Migrant groups that arrive due to state policy are in a different position. They do not have pre-existing institutions for resolving the inevitable violent skirmishes that mark inter-ethnic cohabitation. They are vulnerable to pogroms and therefore seek protection from the state. The state has an obligation to them, or a particular interest in appeasing important constituents. Thus states get implicated into sons-of-the-soil conflicts with migrants, but may be better able to keep out of or prevent communal conflict between indigenous groups in multi-ethnic rural areas.

5. Obstacles to Negotiated Settlements
Since governments can foresee – or, at any rate, experience – the costs arising from violent conflict between migrants and sons-of- the-soil, what prevents them from constructing negotiated settlements to these conflicts? Governments surely reckon the political and economic benefits from the migration of poor members of the dominant ethnic group. But that is not an explanation by itself, because they should still have an incentive to avoid the costs of conflict by redistributing some of the benefits by constraining migration or by paying off indigenous groups. In this section we briefly consider the nature of the benefits the motivate central government policies in sons-of- the-soil cases, and then obstacles to Coasian solutions.
Our cases suggest that governments support internal migration for three main reasons. First, this can be a strategy of “nation building” pursued to fulfill nationalist ideology, to lower the risk of effective separatism, or both. For example, the Mohajir migrants into Sindh gave the Pakistani government a plausible nation-building story to further their political and economic aims. They put forward the theory that the adoption of a single language, Urdu, would guarantee national integration. In doing so, the government managed to put all those whose mother tongue was Urdu (including the Mohajirs but not the Sindhis) at a net advantage in terms of educational opportunities and jobs. More abstractly, because of the critical role of the Mohajirs in the creation of Pakistan, its political élite saw themselves as the standard bearers of the Pakistan "idea" (Rashid and Shaheed 1993).
For the Moros of the Philippines, rebellions against state authority go back a few hundred years. The Americans under the governorship of Taskir Bliss tried to incorporate Mindanao into the Philippine nation. A Moro Province was created in order to aid in its integration into a future Philippine state. Common law was introduced, slavery outlawed, schools were built, a head tax was instituted, and Filipino Christians from the Northern provinces were encouraged to migrate. The long-term goal of nation-building was at least part of the motivation in the encouragement of further migration (Che Man 1990, 49).
“Nation building” is often thought of as the benign cousin of war-inspired “state building” (Tilly 1985), but it can be genocidal. In the Chittagong Hills in 1977, according to Mey, “The Bangladesh government secretly circulated a letter to every army officer now stationed in the Chittagong Hill Tracts, encouraging them to marry tribal girls with a view to assimilating the tribal people.” He claims as well that there is evidence of forced sterilization, amounting to 50-55 women per day (Mey 1984, 150-56). In another report from Laogang, an army officer told the settlers working with the army “to start killing men but to take away women so that at least the next generation of Chakmas will behave like good Bangladeshis” (Amnesty International 1986, 22). Put another way, as one anonymous reviewer pointed out in regard to the Sri Lankan case, the Sinhalese (the nation-builders) saw themselves as sons of all Sri Lankan soil, and saw Tamils as the cultural threat. Eliminating such cultural threats is a nation-building tactic.
The goal of fulfilling a nationalist program is typically complemented by an international strategic imperative of ensuring the state’s existing borders, often in the face of concern about hostile or opportunistic neighboring states. For example, the Chinese government views Han settlers as insurance against Uighur and Tibetan separatism, which could weaken the state’s position with respect to India and Russia (Fravel 2008). This motivation is present in almost all of our cases.
More prosaically, governments can have reasons to want to appease their support base by giving poor members of the dominant ethnic group opportunities to get land – migration policy can be popular. For example, in 1979 President Ziaur Rahman presided at a secret meeting to settle 30,000 Bengali families living in the Chittagong Hills Tracts, and given the popularity of this scheme, the government upped the number to 100,000, and gave generous grants for resettling there. By 1982, a third phase envisioned another 250,000 (from Anti-Slavery Society reports). Gaining popularity among members of the majority group (the migrants) may make the costs of counter-insurgency (against the indigenous) appear small.
Finally, state authorities may have a legitimate interest in the economic development of regions that have vast potential that the indigenous population does not or cannot exploit. In Sri Lanka, the British as far back as 1935 enacted the Land Development Ordinance (#19) in the Dry Zones with the hope of reducing unemployment in the Wet Zone, increasing total rice production, and in the course of meeting those goals, to develop infrastructure and eliminate malaria in the Dry Zones (Gold 1977, 57). In rural Sindh a major source of grievances emerged with the controversial allotments, to military and civil bureaucrats, of land brought under cultivation by the construction of barrages (river control devices). Migrants, from the point of view of the state, are more likely to take advantage of such infrastructural investments, and induce a lift to GDP that might not be possible if the newly cultivatable land were given to the indigenous population. In West Papua (Irian Jaya), the population is about 1.8 million, with about 770,000 of them migrants brought into the territory under the government’s “transmigration” policy, supported by the World Bank. World Bank support suggests that there has been at least some element of economic development goals in the state support for the migrants. About 10,000 families per year were government “sponsored,” though many others come on their own accord. Papuans have been projected to become a minority in their own territory with limited property rights (Suter 1997, 23). It is in this context that the Free Papua Movement (OPM) arose, which was in guerrilla action against and has now declared independence from the Indonesian state.
Despite these various benefits, there are obviously costs, sometimes quite significant, if the consequence of migration is a persistent low-intensity war. Could the state cut deals with the indigenous concerning the pace or amount of migration, for example? In principle they could, but in practice it may be hard for the state to commit to enforce the terms. Early migrants lower the costs for friends and relatives to follow their path, and even limited migration weakens the strength of the indigenous group’s implicit threat to rebel if the state reneges in the future. Further, if indigenous groups accept government assurances, officials may take this as a signal of quiescence or weakness, and renege on their promise by supporting higher levels of migration (Fearon 2008).
Consider the problem the British faced in regard to the Bengali peasants migrating to Assam. These cultivators slowly began moving into the Sylhet and Gaolpara districts of Assam when health conditions improved in the late 19th century. Newer migrants moved up to the Brahmaputra valley, always moving into waste lands and settling there. Migration increased during the Bengal famine of 1942, and continued in the 1950s (even after Partition) when the migration became international (and illegal). Many Assamese complained that the Muslim League was encouraging the migrants. Yet once the migration route was established by state authority, it developed a momentum of its own. The British tried to stem the migration tide. The Line System in 1920 prevented migrants from entering some tribal areas. But this merely redirected migrants from the hills to the plains (Weiner 1978, 95-102, 109).
States may try to commit, but without success. In Assam, with Janata in power in both Delhi and Assam, local police were instructed to find and deport “foreigners”. But with the fall of Janata in 1983, Assamese rebels blamed what they reckoned as illegal voting registration of Bengali foreigners on the newly installed government, and violence resumed. Thus the Janata policies of the 1970s could not commit the Indian state in the 1980s (Chattopadhyay 1990, 4-5). In Andhra, a “Gentlemen’s Agreement” (brokered by the Prime Minister) that had assured opportunities for Telenganas was subverted by Andhras through the production of bogus domicile certificates (Weiner 1977, 221-23). Furthermore, what the state authorities work out may be undermined by other branches of state power. The “Public Employment (Requirement as to Residence) Act” of 1957 permitted the Andhra government to impose domicile rules for lower level government employees (the NGOs, or nongazeted officers). But this was undermined by a decision of the Andhra High Court in 1969 that the State Electricity Board did not come under the purview of the act. This ruling set off the violence of 1969. A few months later India’s Supreme Court declared that portion of the act unconstitutional, since residence requirements within a state was not permissible. Another round of violence ensued.
This inability of the state to commit to a policy of restricting all future migration into areas claimed by sons-of-the-soil helps explain the significant duration of this type of civil war. If duration were merely a function of showing resolve, after several years relevant information about resolve should be revealed. Yet the Moros have been fighting for 30 years, the West Papuans for 35, and some of the Burmese sons-of-soil for a half-century. By contrast, if duration is a function of the inability of the government to commit to a peace agreement, a negotiated settlement can hardly be sustained. This especially burdensome commitment issue for sons-of-soil type civil wars helps explain not only their outbreak, but their duration as well.
Second, states that give into the demands of indigenous groups to limit migration may worry about inviting similar demands from other groups (Walter 2006). Rulers may fear that concessions to indigenous groups might help activate other groups into sons-of-the-soil movements for economic gain at the expense of perceived exploiters. States can face a never-ending spiral of sons-of-the-soil movements. For example, India conceded local autonomy to nativist Assamese. But the victory of the Assamese launched a counter attack by the Bodo Sahitya Sabha, pressing for the creation of a union territory of the Bodo regions outside the ambit of Assam. In the late 1980s, when Upendra Nath Brahma became president of the ABSU (All Bodo Students’ Union), he led the entire movement with diatribes against “Assamese Chauvinism”. Rajiv Gandhi’s government, however, paid little attention to this issue. In 1987 the ABSU held a big rally in Gauhati with a 92-point program, and upon returning home, one group of Bodos was violently attacked by a group of Assamese youth, with one death (Bhattacharjee 1996, chap. 4). In 1989 after a bout of terrorist violence, the ABSU formed a Bodoland Autonomous Council (BAC), which was able to procure for the Bodos legal autonomy for social, economic, educational, ethnic and cultural matters. Next, however, the aboriginal Koch-Rajbongshi population mostly within now-official Bodoland staged a protest demanding their right to self-determination. Of the 1.8 million people living in Bodo villages, 1.2 million are Koch-Rajbongshi, and now their fate was, according to one spokesman, “at the mercy of the Bodo leaders in the name of geographical contiguity of the BAC area…” Other Bodo organizations argued about getting as yet excluded villages into the zone of the BAC. State authorities, to the extent that they side with the indigenous, may be in for a never-ending set of autonomy demands. In Assam, it wasn’t only Assamese, Bodos and Koch-Rajbongshis. The Nagas pressed for Nagaland and other tribal groups did similarly, with the result that Assam has been broken up into discrete cultural-political units (Weiner 1978, 120-22).
A central state’s fear of future challenges may lead it to rationally want to “screen” violent challengers by fighting for a time before being willing to make political concessions (if the rebel movement survives the fighting period).
If there are substantial political or economic gains to the center from enabling internal migration, then a Coasian solution could involve compensating the indigenous using some of these gains, thus buying off violent opposition. Even if the center can’t commit to prevent continued migration, why couldn’t it commit to pay such compensation as migration proceeds?
As seen in the case of Malay-Muslims in Thailand, paying off the indigenous population in public goods (an excellent school system in the dominant language, one that provides good social mobility prospects) can contribute to staving off rebellion. It is also theoretically possible to pay off the most disaffected among the indigenous in private handouts in order to alleviate pressures for rebellion. Lustick (1980) analyzed a system of control mechanisms in Israel inside the Green Line, one element of which was co-optation of elites. This system of control pacified the indigenous Arab population that was outraged by the massive migration of Zionists into Palestine.
For this solution to be feasible, the center must be able to buy off the indigenous group with one large, “up front” set of transfers, or it must able to commit to continue to provide transfers as migration continues. The latter may not be credible. The center’s motivation to buy off violence depends on the threat of violence by indigenous rebel groups, and this threat will diminish as the migrants gain a stronger position in the region. A single large “upfront” transfer may be politically (or even financially) infeasible, and short of paying to resettle the indigenous in another country, transferred assets would not be secure from later expropriation.
Still, this solution may be and, to some extent, has been feasible for periods of time in some of our cases. We have no theory to explain the variation. We observe, however, that poor states may be less able to provide satisfactory compensations to disaffected groups than are richer states. The success of the Thai economy not only allowed for social mobility hopes for Malays within Thailand, but it allowed for private pay-outs to disaffected Malays (though we do not know if such pay-outs were in fact made). Certainly the costs to Israel of buying off the Arabs were heavy, but significantly defrayed by donations from the Jewish diaspora.

6. Conclusion
We have argued that a substantial fraction of ethnic civil wars since 1945, many of which continue today, follow a common pattern and have a common set of escalatory dynamics. Conflict emerges between members of a minority ethnic group that considers itself to be the sons-of-the-soil and recent migrants from other parts of the country. The migrants are typically members of the dominant ethnic group who have come in search of land or jobs in local bureaucracies, sometimes encouraged by economic incentives provided by the state. The violence often begins as communal conflict (riots, pogroms, gang attacks), but escalates to civil war levels if state forces intervene on the side of migrants. Because migration tends to proceed slowly and continuously and because the sons-of-the-soil are usually a small, weak group compared to the center, these conflicts tend to be very long-running but of low intensity.
Identification of this set of cases helps resolve at least one puzzle in the recent literature, namely, why is there a strong correlation between country population and civil war onset? It seems that the correlation arises almost entirely because large countries have been prone to SoS conflicts. So it is unlikely that large population per se causes a higher risk of civil war, and we should not expect population growth in any given country to raise onset risk unless this were to significantly increase internal migration to rural areas inhabited by presumptive sons-of-the-soil.
Another puzzle in the civil war literature concerns what role “grievances” play in explaining internal conflict. Let’s say that an individual has a greater political or economic grievance the greater the individual’s unhappiness with the status quo on some policy dimension (or dimensions). The argument that, other things equal, civil conflict should be more likely the greater and more widespread are grievances in this sense seems quite compelling on its face. But the cross-national statistical literature on civil war onset has found little evidence of a link between plausible indicators of widespread grievance – such as autocracy, repression, or inequality – and greater risk of internal war.
Elsewhere we have offered the following possible explanation (Fearon and Laitin 2003): Civil war risk is not very sensitive to variation in average societal grievances, because most civil wars develop out of conflicts with small rebel groups, for which the key constraints are not finding aggrieved supporters but rather the ability to survive against state forces. If so, then there may almost always be subsets of intensely aggrieved individuals who would be interested in getting a rebellion going if circumstances permitted. Cross-country variation in civil war onset would then be better explained by variation in those circumstances than by variation in broad social grievances.
Another – not mutually exclusive – possible explanation is that the “other things” are not equal in the cross-sectional comparisons behind the non-findings on measures of grievances. That is, grievance levels are partly chosen by governments with their choice of policies, and they surely make these choices with an eye to the probability of resistance. Thus grievances may be greater in a country in part because the government is strong enough relative to the aggrieved to get away with harmful policies. If grievances are endogenous in this manner, then we would need research designs that identify exogenous shocks to grievances in order to identify an effect of increased grievances on civil war risk.
The increase in sons-of-the-soil grievances as a result of in-migration by the dominant group is not a wholly exogenous shock, since, to varying extents, governments permit migration to occur. But nonetheless it is a change over time within a country. The cases we have discussed suggest that this increase in grievance can produce civil war. Relative capabilities must still be important, however, since we find that migrant groups almost never rebel if they are aggrieved by the state deciding to side with the indigenous. We have suggested that this is because the members of migrant groups have better exit options than do the sons-of-the-soil; that sons of the soil may have advantages for rebellion associated with having a regional base; and that the pressures for ongoing migration may make it difficult to construct stable peaceful settlements between the state and the indigenous group.
Aid to support development schemes in areas with indigenous ethnic minorities has attracted considerable criticism and controversy, with reasonable concern focused on very small tribes in Asia and Latin America whose capacity to resist rarely rises to the level of civil war. The evidence and analysis above argues for seeing such cases as part of a broader phenomenon that can involve larger minorities and sometimes quite substantial ethnic civil wars.

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