This article advances a theory of responsibility attributions in which such judgments are rooted in considerations of intensity and comparability. Informed by insights from the study of attitudinal ambivalence, the article contributes to the attribution literature in three important ways. First, we propose a new technique for measuring responsibility judgments, one that explicitly incorporates information about intensity and comparability into a single scale. Second, from a methodological standpoint, we demonstrate that our new measures of comparative responsibility ratings have greater construct validity than traditional ratings-based measures and outperform them as predictors of political evaluations. More substantively, we show that comparative responsibility ratings are politically consequential and strongly influenced presidential approval, presidential vote choice, and congressional vote choice in the United States during the 2012 elections.