Civil war intervention literature identifies colonial history as influencing the likelihood of interventions. This literature, however, has yet to clarify the mechanisms through which colonial history influences interventions. We develop and test an argument linking the relations established by colonialism—economic, political, and social—with interventions. We find that colonial history influences interventions, but its effect matters less once we control for these three relations. Importantly, we find that this effect of colonial history is particularly small in dyads with stronger economic relations. Our paper gives further credence to liberal arguments emphasizing the role of economic factors in international security.