When does politics stop at the water's edge? A QCA of parliamentary consensus on military deployment decisions

Why do some military deployment decisions lead to high levels of political contestation, whereas others do not? Or, put differently, when does parliamentary consensus on the use of force abroad exist? In this article, we aim to answer this question by focusing on the varying levels of consensus in national parliaments when taking military deployment decisions. We do so by examining conditions that were derived from research on the domestic-level determinants of the use of force, parliamentary voting, and opposition behaviour. These conditions were included in an integrated theoretical framework, which we tested with fuzzy set Qualitative Comparative Analysis. The results of our analysis show that the international legal status and the objectives of the military operation are of crucial importance for explaining the pattern of political contestation. However, domestic variables need to be taken into account as well to fully explain the level of political contestation of military deployment decisions.