Little-mentioned but often-said is Trump's other catchphrase: "there's something going on." It's used to insinuate a conspiracy, to trigger feelings of paranoia and fear in his audience without committing to specifics. He screwed up over the weekend and attached it to a too-concrete suggestion that President Obama was somehow involved in the Orlando nightclub massacre.
In the fallout, he ended up withdrawing the Washington Post's credentials to cover his rallies and press events after the newspaper reported plainly on his remarks. So who better than them to explain that now-obvious phrase's meaning?
That phrase, according to political scientists who study conspiracy theories, is characteristic of politicians who seek to exploit the psychology of suspicion and cynicism to win votes.
The idea that people in positions of power or influence are conspiring to conceal sinister truths from the public can be inherently appealing, because it helps make sense of tragedy and satisfies the human need for certainty and order. Yet politicians hoping to take advantage of these tendencies must rely on vague and suggestive statements, since any specific accusation could be easily disproved.
"He's leaving it to the audience to piece together what he's saying," said Joseph Uscinski, a political scientist at the University of Miami, in a recent interview.