Donald Trump has faced unprecedented opposition from members of his own party to his candidacy, election, and presidency. This opposition, known collectively as #NeverTrump Republicans, opposes Trump for a variety of reasons, but is united in its assessment that he is temperamentally unfit to be president. The contributors in The Republican Resistance: #NeverTrump Conservatives and the Future of the GOP detail the origins of this movement, with particular focus on the 2016 election cycle, and explore how #NeverTrump opponents have continued their resistance through the Trump presidency. The contributors argue that the Trump presidency and the #NeverTrump opposition represent a key feature of modern American politics in which both major American political parties must contend: the rise of a populist insurgency intent on overtaking the party from within. The Republican Resistance examines the implications of this populist revolt on the GOP and the challenges of embracing demographic and structural realities on the one hand while catering to a political base built to oppose those trends on the other.