There are two immediate reasons that President Trump might have decided that, after weeks of holding his fire, it was worth disparaging Christine Blasey Ford during a rally in Mississippi on Tuesday night. The first is that Ford’s allegation that Trump’s nominee to the Supreme Court, Brett M. Kavanaugh, had assaulted her when the two were in high school was putting Kavanaugh’s nomination at risk. Trump insists that he punches his opponents only after they punch him first, which isn’t true, but it’s certainly unusual for him to incur political damage without lashing out. On Tuesday, that moment arrived for...