Examines the sources of domestic political will for intervention, particularly the role of partisanship, ideology, and public opinion on Congressional members' willingness to support US intervention for humanitarian purposes. Analyzes several Congressional votes relevant to four episodes of US humanitarian intervention: Somalia, Haiti, Bosnia, and Kosovo. Finds that public support for humanitarian intervention increases Congressional support and that other political demands, primarily partisanship and ideological distance from the president, often trump the normative exigencies of intervention.