This paper provides a comprehensive assessment of the effect of Fox News Channel (FNC) on the mass public’s political preferences and voting behavior in the United States from 2000 to 2020. We show that FNC has shifted the ideology and partisan identity of Americans rightward. This shift has helped Republican candidates in elections across levels of U.S. government over the past decade. Our estimates suggests that an increase of 0.05 rating points in Fox News viewership, induced by exogenous changes in channel placement, has increased Republican vote shares by at least 0.5 percentage points in recent presidential, Senate, House, and gubernatorial elections. Our findings have broad implications for political behavior, elections, and the political process in the United States.