The role that emotions play in shaping mass political behavior is increasingly well researched. This study refocuses the debate to explore the effect that the emotions expressed by candidates (target affect) through new media have on participation, rather than the effect of emotions felt by voters (observer affect). A unique experiment embedded in a nationally representative online survey demonstrates that appeals invoking target affect can strongly increase citizens’ political participation both online and offline. Contrary to fears that the use of emotions by political elites will agitate the least knowledgeable citizens, however, the results demonstrate that it is the most politically-engaged citizens who are mobilized by such appeals. These findings have significant implications for our understanding of the participatory consequences of emotional political messages on the Internet.