Donald Trump's surprising election as president of the United States in 2016 marked the emergence of a massive anti-Trump movement, which featured local organizing in elections, legislative lobbying, and a series of mass demonstrations. The movement offered a very broad umbrella of diverse constituencies, causes, and approaches to social change, providing additional attention to virtually all of those causes. Elements within the movement exercised influence in stopping the repeal of the Affordable Care Act, winning the Democratic Party a majority in the House of Representatives in 2018, and defeating Trump's reelection bid in 2020. It's likely to be difficult to find sources of unity after Trump's defeat. The movement offers an extraordinary opportunity to see the connections between protest politics and institutional action, including elections.