Former Texas Rep. Ron Paul says a yearlong economic boom under President Trump is “a bit of an illusion” and that debt, inflation, and inequality could cause turmoil that benefits a “hardcore nucleus” of libertarians. The libertarian Republican leader told the Washington Examiner that Trump could face a strong challenger in the 2020 GOP primary, especially if “things are really much worse." “The big opening for us is the fact that this system is coming apart. We’re on the verge of something like what happened in ‘89 when the Soviet system just collapsed,” he said. “I’m just hoping our system...