Past studies examining the international conflict behavior of parliamentary democracies have reported inconsistent findings and produced some empirical puzzles. One of the main puzzles is that, despite a strong theoretical basis for expecting coalitional majority cabinets to be less conflict prone than single-party majorities, most studies found no difference in their conflict behavior. Still others report coalitional governments to be more conflict prone than single-party ones. In this study, I show that these empirical inconsistencies can be resolved once we take into account the ideological composition of the cabinet. The main contention is that relatively marginal coalitional partners may have a disproportionate influence when the government faces risky decisions, such as the initiation of international disputes. The key lies in their greater bargaining leverage in intra-coalitional politics, which is subsequently reflected in their influence over foreign conflict decisions. More generally, this study shows how different degrees of ideological diversity or cohesion abate and/or accentuate a state's conflict behavior. The expectations are tested empirically, and the findings more robustly predict the conflict behavior of parliamentary regimes than do the results of previous research.