The most consequential moment from Donald Trump’s glitchy interview with Elon Musk on Monday came during a discussion of government cost-cutting. “Well, you, you’re the greatest cutter,” Trump told Musk, before launching, apropos of nothing, into a reverie about how Musk dominates his employees. “They go on strike,” said Trump. “I won’t mention the name of the company, but they go on strike and you say, ‘That’s OK. You’re all gone. You’re all gone. So every one of you is gone,’ and you are the greatest.”Trump’s sympathy with plutocrats over unions is not a surprise, given both his record in...