Does Terrorism Influence Domestic Politics? Coalition Formation and Terrorist Incidents

Terrorism has been shown to influence domestic politics, for example, by altering the priorities of voters and politicians. This article argues that terrorism has broader political consequences than simply putting national security on the political agenda. In particular, it argues that terrorist activity influences government formation. A number of scholars have noted that the presence of an external threat provides an incentive to overcome internal disagreements, suggesting that larger and more inclusive coalitions should form. Terrorist activity may also influence government survival, as voters hold politicians accountable for failing to provide security. Politicians, in anticipation of terrorist activity, may, therefore, seek to form a more stable coalition. The literature on government survival suggests that the size of the coalition positively affects its durability but that its ideological breadth is expected to have an adverse effect on survival, which is the opposite of the prediction of the theory based on external threat. To test whether terrorism influences coalition formation, the author analyzes coalition formation in 17 (primarily Western European) parliamentary democracies over a 50-year period using data on domestic and transnational terrorism from, respectively, the TWEED dataset and the Terrorism Knowledge Base. The results show that government coalitions are more likely to be surplus coalitions and, consistent with the theory emphasizing government survival, more likely to have a low degree of ideological polarization in periods following terrorist activity.