Sign up for the Slatest to get the most insightful analysis, criticism, and advice out there, delivered to your inbox daily. Now President Trump has gone too far. Last week, he committed more foreign policy heresies than any U.S. leader ever has, slamming Ukraine’s popular president, Volodymyr Zelensky, as a dictator; bypassing Ukraine and the rest of Europe in seeking a separate peace with Russia; and all but endorsing a neo-Nazi party in Germany’s elections, thus casting doubt on America’s commitment to Western security and values. On Monday, he went a step beyond what even many of his critics had...