Partisanship structures mass politics by shaping the votes, policy views, and political perceptions of ordinary people. Even so, substantial shifts in partisanship can occur when elites signal clear differences on a political issue and attentive citizens update their views of party reputations. Mismatched partisans who strongly care about the issue respond by changing parties in a process of “issue evolution” when writ large. Others simply update their views to match their party in a “conflict extension” process. We build on these models by integrating the largely separate research strands of party issue ownership. Using sexual misconduct as a critical case study, we argue that partisan change can occur rapidly when party elites move strategically to take ownership of an issue, thereby clarifying differences between the parties. Using a quasi-experiment, a survey experiment, and data from dozens of national surveys, we find recent, rapid shifts in party reputations on #MeToo, views of the issue, party votes, and broader party support.