Terrorism is an instrument for groups that cannot achieve their political goals legally. One important strategic function of terrorism is to weaken the government -either directly by attacking representatives or supporters of the government or indirectly by causing a political response, which is unpopular among the population. Often, however, political stability of the home government is buttressed by foreign powers. In this case, the terrorists can have a strategic interest in attacking nationals of these foreign countries. This paper analyzes this logic by looking at international alliances as a proxy for international support. If the friend of my enemy is my enemy, then terror entrepreneurs, which seek to overthrow their home country's government (the enemy), may find it attractive to target nationals of the foreign allies of their country (the friends of the enemy). Our theory predicts that attacking nationals of a foreign ally is particularly attractive if this ally is militarily more powerful than the home country. Moreover, the combined effect of alliance and relative power differentials becomes stronger the more democratic the ally and becomes weaker the more democratic the terrorists' home country. We find empirical support for our hypotheses in an analysis of a directed country dyad sample of international terrorism. 2
IntroductionWhy do terrorists from one country target nationals of another country? The fast growing literature on terrorism, which has focused on the root causes of terrorism (Abadie 2006), is surprisingly ill-equipped to answer this question. On a theoretical level, research has neglected the impact of links between the terrorists' home country and the victims' country on patterns of international terrorism. This has translated, on the empirical side, into studies that aggregate acts of terror at the country level (of the terrorists or the victims or the location of terror). These studies have generated insightful results. Yet, by design they are not capable of analyzing why terrorists from one country target nationals from some foreign countries, but not from others.
1Starting from the assumption that terror groups want to gain a significant political influence on their country of origin or the broader region (Crenshaw 1981(Crenshaw , 2001Pape 2003Pape , 2005Kydd and Walter 2006), terror groups should mainly attack domestic targets. However, some governments borrow strength from more powerful allied foreign powers. Citizens from countries that stabilize the government in the terrorists' home country may then become a derivative, strategic target of terror attacks. If the friend of my enemy is my enemy, then terrorist groups, which seek to overthrow their country's government (the "enemy"), will find it attractive to target nationals of the foreign supporters of their country (the "friends of the enemy").
1The only directed country dyad studies of terrorism we are aware of are Krueger and Laitin (2008) and Blomberg and Rosendorff (2006).
3In this paper, we study one important w...