This article reviews the literature on the onset and dynamics of domestic terrorism, with special emphasis on the interactions between terrorist organizations, the state, and society. Because this literature has often been based on case studies, we seek to impose some structure to its findings. We challenge the distinction between domestic and international terrorism, which truncates the sample of violence, and we show that the actor-sense of terrorism (violence carried out by underground organizations) is the most appropriate model for causal analysis. Terrorist organizations tend to emerge in developed countries in which the state is able to prevent the loss of control over any part of its territory. Terrorists take advantage of the state's mistakes (when, for example, it is over-repressive or makes ineffective concessions) in order to boost their support. Terrorists cannot survive without some degree of support. Consequently, levels of violence and targets are determined by social constraints. Copyright © 2009 by Annual Reviews. All rights reserved

This book argues that nationalist violence in developed countries is the product of unresponsive political elites and nationalists blocked from attracting supporters through legal channels. Political elites are prone to ignoring a regional polity when their clout in that region is negligible and they do not rely on the region's support to maintain their positions of power. Conversely, when nationalists cannot make inroads through legal channels, incentives for violence are ripe. Thus, when nationalists in postwar Europe found elites unresponsive, it was state repression that helped radicals build a new group of support around militant action. The larger this new constituency legitimizing violence grew, the longer the conflict lasted. The book elucidates this complex dynamic through a deft combination of theoretical modeling, statistical methods and comparative case studies from the Basque Country, Catalonia, Corsica, Northern Ireland, Sardinia and Wales.

We deal in this article with the relationship between ETA attacks and electoral support for Batasuna, its political wing. We show that the relationship is twofold, since the geographical distribution of electoral support for the terrorists affects the location of ETA attacks, but violence also influences electoral support for the terrorist cause. On the one hand, when ETA chooses a location for its attacks, it takes into account the electoral strength of Batasuna. Our results show that the higher the vote for Batasuna in a municipality, the more likely members of the security forces will be killed there. With regard to the targeting of civilians, the relationship is curvilinear. ETA kills civilians in municipalities that are polarized, where support for Batasuna falls short of being hegemonic. On the other hand, our results also show that ETA attacks have an effect on the size of its support community. When ETA kills members of the security forces, voters punish the Batasuna party electorally. In the case of civilians, it depends on the specifics of the various campaigns. We find that when ETA kills informers and drug-dealers, the vote for Batasuna increases. ETA's killing of non-nationalist politicians, however, decreases Batasuna's vote share

This article analyzes the choice of tactics by armed groups. We claim this choice is largely determined by the capacity of the rebel groups to control territory. Groups that are not able to liberate territory remain underground and have to rely mainly on bombings. Groups with territorial control engage in guerrilla-like attacks in which there is a physical encounter with the enemy. This conjecture is tested and largely confirmed at three levels: a cross-sectional analysis of the distribution of tactics in 122 armed groups, using compositional data analysis; a geographical analysis of the distribution of tactics in the largest cities as opposed to the rest of the country; and a case study of Hezbollah.

The large-n literature on political violence has paid little attention to the distinction between insurgencies that control territory and those that do not. Territorial control has consequences for the lethality of the group, its pattern of recruitment and bargaining power. The main determinant of territorial control, we argue, is state capacity: while territorial insurgencies are more frequent in poor countries, nonterritorial ones tend to occur in countries with intermediate levels of development (rich countries are free of internal violence). The authors show that the relationship between development and nonterritorial violence is a concave one, using a panel for the period 1970–1997 that combines existing data sets on civil wars and the Global Terrorism Database 1. The authors also find that nonterritorial violence is more likely in democratic, old states. Population, rough terrain, and inequality have a similar impact on both types of conflict. The authors discuss to what extent territorial conflicts correspond to civil wars and nonterritorial ones to terrorism.