We talk to the historian Sarah Churchwell about the origins of some of the ideas churning up politics in the age of Trump: 'America First', 'Make America Great Again', 'Fake News'. Where do these phrases come from and what do they mean? We try to unpick the racism from the isolationism and the anti-immigrant from the anti-elitist sentiment. Plus we discuss whether fascism in America was a real threat in the 1930s and whether it's a real threat today. With Andrew Preston, historian of US foreign policy. Next week: the midterms!