A Republic, Not an Empire, by Pat Buchanan. Since Pat is a right-winger, his noninterventionism would get a more respectful hearing from Trump and his supporters than a left-wing version would. This is an excellent work of American history, and its foreign-policy recommendations are just right. The Revolution: A Manifesto, by Ron Paul. This is the kind of book that converts people. And it hones your instincts: once you hear its arguments, you instinctively know the right position on matters ranging from money to foreign policy to the Constitution.