Donald Trump hadn't said 300 words during his announcement speech before he called Mexican immigrants rapists. Even before that, he'd already made fun of his sweaty opponents and President Obama. But by word 300, he'd already made the comment that prompted a backlash from Univision — a backlash that drew new attention to his hard-line stance on immigration and, by extension, moved him into first place in the polls. Trump mocked Vietnam veteran John McCain's war record. He made a comment about Fox News's Megyn Kelly that was widely interpreted as referring to her menstruation. He retweeted a joke about...