The effects of the electoral calendar on terrorist attacks

• We study the linkage between terrorist events in democracies and elections.
• We examine transnational and domestic terrorist trends over a 40 year span.
• Transnational terrorist events decline before elections.
• Domestic terrorist events increase before elections.

The goal of this paper is to study the linkages between the timing of terrorist events and elections. As strategic actors terrorists may respond to electoral environments by altering the frequency of their attacks around election times. Focusing on democracies, we examine variations in transnational and domestic terrorist incidents before elections over a 40 year span. We find distinct pre-electoral changes in the incidence of terrorist events. In the ITERATE data set, where only transnational terrorist events are included, terrorist activities decline in election months, while in the partitioned GTD data set, where only domestic terrorist events are kept, terrorist activities rise in election months. The findings suggest electoral calendars can dissuade and attract terrorist threats, depending on the origin of the threat, but these effects occur only very close to election time.