Just a few thoughts on the risk of a war between conservatives and populists on the right:
Conservatism has a long tradition of pluralism, so the attempt to purge all dissenters might at once run afoul of conservative tradition and be politically counterproductive. You can still be a conservative and oppose TPP (and even “free trade” in general–unless Calvin Coolidge doesn’t count as a conservative anymore). Likewise, you can still be a conservative and support “amnesty” or “comprehensive immigration reform” or the Gang of Eight bill.
Furthermore, there’s room for conservative-populist compromise on a variety of issues. The current populist surge points to the blind spots of contemporary political debates. One of the jobs of political movements is to identify and to speak to underlying problems, so people who want conservatism to live as a political movement have a great incentive to address these challenges. Luckily, conservatives can indeed address them.