Why do business leaders support or oppose interstate wars? This article clarifies and empirically illustrates two competing perspectives on the sources of business war preferences: the opinions businesses have about interstate conflict. Namely, while an “economic consequences” perspective argues that business war preferences stem primarily from the economic effects of interstate conflicts, a “leader ideology” perspective predicts that business leaders’ domestic policy preferences and political ideology will determine their war preferences. I reexamine historical survey data on American business leaders’ opinions about the Vietnam War using item response theory scaling and regression analysis and find support for both perspectives. These results point toward the importance of further theoretical and empirical research on the sources of business war preferences, so I propose a structured, forward-looking research agenda on business war preferences based on different conceptualizations of businesses, their motivations, and the consequences of interstate conflicts.