So this just actually happened. Via Politico:
Donald Trump on Tuesday said “the Second Amendment” may be the only way to stop Hillary Clinton from getting to appoint federal judges if she wins the presidential election in November.
“Hillary wants to abolish, essentially abolish, the Second Amendment,” he said, in what appeared to be a joke. “By the way, and if she gets to pick her judges, nothing you can do, folks. Although the Second Amendment people, maybe there is, I don’t know. But I’ll tell you what, that will be a horrible day.”
The reference to the Second Amendment, the right to keep and bear arms, could be interpreted as a joke about using violence to stop Clinton or her judicial picks.
Ok, enough. This psychopath @RealDonaldTrump just dog-whistled to his supporters to shoot the opposing candidate.
— Keith Olbermann (@KeithOlbermann) August 9, 2016
Watch the guy seated behind Trump react as he says it. Appears to say "whoa" or "wow." https://t.co/5iZCS9ybVV
— Dave Itzkoff (@ditzkoff) August 9, 2016
Trump joking about someone shooting Hillary is sick & dangerous. It's how unbalanced people are inspired to murder. It trivializes violence.
— Garry Kasparov (@Kasparov63) August 9, 2016
"TERRIFYING": Trump appears to encourage gun-rights advocates to shoot Hillary Clinton https://t.co/abJxiwWqed pic.twitter.com/CUdGaZHgSE
— New York Daily News (@NYDailyNews) August 9, 2016