Recent scholarship argues that how members of Congress respond to an ongoing war significantly influences the president's strategic calculations. However, the literature is comparably silent on the factors influencing the public positions members take during the course of a military venture. Accounting for both national and local electoral incentives, we develop a theory positing that partisanship conditions congressional responses to casualties in the aggregate, but that all members respond to casualties in their constituency by increasingly criticizing the war. Analyzing an original database of more than 7,500 content-coded House floor speeches on the Iraq War, we find strong support for both hypotheses. We also find that Democrats from high-casualty constituencies were significantly more likely to cast antiwar roll-call votes than their peers. Finally, we show that this significant variation in congressional antiwar position taking strongly correlates with geographic differences in public support for war.