Washington: There have been enough political assassinations in the US to make chirpy or even oblique allusions to death on the campaign trail the worst of bad taste.

So when Donald Trump went there at a rally on Tuesday, it was a sinister moment in a campaign already replete with ugly moments.

It was hardly surprising that critics piled on - from assassination attempt survivor and former congresswoman Gabrielle Giffords to Connecticut senator Chris Murphy, whose electorate includes the Sandy Hook school, where 20 children and six staff were massacred in 2012.

Giffords gave Trump the benefit of the doubt, but she still laid into him: "Responsible, stable individuals won't take Trump's rhetoric to its literal end, but his words may [prove] a magnet for those seeking infamy.

"They may provide inspiration or permission for those bent on bloodshed."

Murphy tweeted: "Don't treat this as a political misstep. It's an assassination threat, seriously upping the possibility of a national tragedy and crisis."

And later: "Unstable people with powerful guns and an unhinged hatred for Hillary are listening to you,@realDonaldTrump."

In an attempt at damage control, Trump's aides quibbled on the interpretation, but in an era of dog-whistle politics, the implication of the words that came from Trump's mouth were this - gun rights enthusiasts might have to take matter into their own hands because, by stacking the Supreme Court, Hillary Clinton as president would be able to do away with the Second Amendment, which guarantees the right to bear arms.

Talking about what "a horrible day" it would be - by which Trump means the loss of the Second Amendment, not the assassination of a president - the Republican candidate resorted to the rhetorical devices by which he often says one thing while meaning another.

"If she gets to pick her judges, nothing you can do, folks," Trump said. As the North Carolina crowd started booing, Trump went on: "Although the Second Amendment people - maybe there is, I dunno."

It's true - deconstructing the meaning of Trump's stream-of-consciousness speeches is challenging. But, by alluding to Clinton picking new judges, Trump seemed to be conjuring with events after a Clinton victory, which would make it difficult for his defenders to argue that he was merely alluding to gun rights supporters voting against her to head off such an eventuality.

And if that was his meaning, why the ambivalent "maybe there is, I dunno"? Even some in Trump's audience seemed shocked - in video clips, a man can be seen behind the candidate's shoulder, looking gob-smacked as Trump speaks and seemingly turning to a companion as though seeking assurance that he had heard what he thought he had heard.

And indeed, the Trump campaign did try to spin its way out of the hole Trump had dug.

Campaign spokesman Jason Miller said in a statement: "Second Amendment people have amazing spirit and are tremendously unified, which gives them great political power. And this year, they will be voting in record numbers, and it won't be for Hillary Clinton, it will be for Donald Trump."

There's often a real or implied violent subtext to Trump campaign events - from the candidate himself and his aides.

In a July radio interview, Trump's adviser on veterans' issues, Al Baldasaro, urged that Clinton should be executed by firing squad. Calling Clinton a "piece of garbage", Baldasaro railed: "This whole thing disgusts me, Hillary Clinton should be put in the firing line and shot for treason."

For the foolhardy, here's an unfiltered transcript of what Trump said: "Hillary wants to abolish, essentially, the Second Amendment. By the way, if she gets to pick, if she gets to pick her judges, nothing you can do, folks. Although the Second Amendment people, maybe there is, I dunno. But I tell you what: that will be a horrible day. If Hillary gets to put her judges in, right now we're tied [in the Supreme Court, after the death of Antonin Scalia]. You see what's going on.

"We're tied 'cause Scalia, this was not supposed to happen. Justice Scalia was going to be around for 10 more years at least, and this is what happened. That was a horrible thing, so now look at it. So Hillary essentially wants to abolish the Second Amendment.

"Now speaking to the NRA folks, who are great: when you, when you, and I tell you, so they endorsed me. They endorsed me very early. My sons are members. I'm a member. If you, we can add, I think the National Rifle Association, we can add the Second Amendment to the justices, they almost go, in a certain way, hand in hand. Now the justices are going to do things that are so important. And we have such great justices.

"You saw my list of 11 that have been vetted and respected and have gotten great, and they, a little bit, equate.

"But if you don't do what's the right thing, you're not going to have - either you're not going to have a Second Amendment or you're not going to have much of it left. And you're not going to be able to protect yourselves, which you need. Which you need!

"When the bad guys burst into your house, they're not looking about Second Amendments and 'Do I have the right to do this.' The bad guys aren't going to be giving up their weapons. But the good people will say, 'Oh, well, that's the law.' No, no. Not going to happen. We can't let it happen. We can't let it happen."

On a re-reading, a sinister interpretation of Trump's "maybe there is, I dunno" is supported by the subsequent reference to "if you don't do what's the right thing" - which could be to vote for Trump, so why not say it?

Once again Trump showed the world that he could turn on a dime. In Detroit on Monday, his careful reading of a speech was offered as proof that the man is presidential; fast forward to Tuesday's rally in North Carolina, and the candidate has gone nuts - again.