This chapter investigates the state of foreign policy opinion within the Republican Party today. Perhaps surprisingly, the basic distribution of voter opinion on foreign policy within the GOP has not changed that much since the early Obama era. However, Republican voters do support Trump, and not only because he is an incumbent president from the same party. The GOP has moved in a populist, culturally conservative, and white working-class direction over a period now spanning several decades. In this sense, Trump is as much an effect as a cause. He has broken open prior conservative orthodoxies. In certain ways, on a range of specific issues following his presidency, this leaves the future of Republican foreign policy wide open. But observers should understand that the conservative-leaning American nationalism he has championed is not about to disappear when he leaves the scene. In one form or another, it is here to stay.