This article explores how political actors use the emotions of fear and anger in what we call fear-anger contests. Our theory distinguishes between governmental and populist actors and posits that, in a contest for media attention and the hearts and minds of citizens, populists pursue a politics of anger whereas governmental actors pursue a politics of fear. To evaluate the theory, we examine two episodes of contentious politics: the 2016 Brexit referendum and the election of Donald Trump in the same year. We rely on automated sentiment analysis, using machine learning and emotion dictionaries to examine a dataset of social media posts on Twitter. In the case of Brexit, we find a fear-anger contest between Remain (“Project Fear”) and Leave (“Project Anger”). In the case of the 2016 US presidential election, we find a negativity contest where both parties reinforce each other’s negative emotions.