Supporters of Donald Trump, left, face off with protesters after the cancellation Friday of a Trump campaign rally on the campus of the University of Illinois-Chicago. (Charles Rex Arbogast/Associated Press)

This column has been updated.

As he edges closer to winning the Republican nomination, it is possible to discern, at intermittent intervals and in trace amounts, an instinct in Donald Trump to act presidential. There was Trump in Thursday’s debate with a paean to the relative civility of the encounter. There was Trump in his Super Tuesday victory lap pronouncing himself a “unifier.”

But Trump being Trump, the presidential urge can never proceed very far before being overtaken by his real self: Trump the bullying thug and Trump the self-pitying victim.

Both aspects of Trump’s personality have been on rampant display over the past several days, as the protests at Trump’s rallies have spun dangerously, predictably out of control.

Trump, reaping a whirlwind of his own creation, could have risen to the occasion. He could have dialed back the taunts. He could have, unlikely as it sounds, expressed just a tinge of un-Trumplike regret.

Republican presidential candidate Donald Trump said, "Isn't it great to be at a Trump rally," as the first of several protesters was ejected from St. Louis rally. (Reuters)

Instead, in a development as disappointing as it was unsurprising, Trump ramped up. “Go home to mommy,” he told one protester in Missouri on Friday. “Get a job,” he told another. “These people are bringing us down, remember that,” he told the crowd. These people. How presidential.

Trump took no responsibility — zero — for the anger his divisive rhetoric has generated among the demonstrators, nor for the violence it has incited among his supporters. He was only sorry the protesters had to be treated so delicately. “They’re being politically correct the way they take them out,” he said. “There used to be consequences.”

To be clear, protesters have a right to be heard — but in an appropriate place and manner. Hecklers are a fact of political life, yet no candidate should have to contend with a campaign event so constantly disrupted the candidate cannot share his own message. The scene of Secret Service agents swarming around Trump after a protester broke through the security barrier at a rally in Ohio on Saturday was an unsettling reminder of the lurking potential for tragedy.

But candidates bear responsibility, as well — for the tone of their rhetoric and for the way they respond, and encourage their supporters to respond, to dissent. Not Trump, though, at least according to Trump.

He says things that are hurtful and divisive, then is surprised when his language provokes a counter-reaction. At that point, he sees freedom of speech as a one-way street — Trump’s freedom to speak — and lashes out at those who would dare to interrupt.

“The organized group of people, many of them thugs, who shut down our First Amendment rights in Chicago, have totally energized America!” tweeted the man who recently vowed to “open up” libel laws so he could sue critics in the media.

And when Trump’s supporters turn, inevitably, violent, his response is more empathetic than condemnatory.

“People come with tremendous passion and love for their country, and when they see protest — you know, you’re mentioning one case, which I haven’t seen, I heard about it which I don’t like,” Trump told CNN’s Jake Tapper at Thursday’s debate, responding to videotape of a Trump supporter punching a protester in the face.

“But when they see what’s going on in this country, they have anger that’s unbelievable. They have anger. They love this country. They don’t like seeing bad trade deals, they don’t like seeing higher taxes, they don’t like seeing a loss of their jobs where our jobs have just been devastated. . . . There is some anger. There’s also great love for the country. It’s a beautiful thing in many respects. But I certainly do not condone that at all, Jake.”

No, nor egg it on. This is a candidate who says of protesters things like, “I’d like to punch him in the face.” Or, “In the good ol’ days, they’d rip him out of that seat so fast.” Or, “Knock the crap out of him, would you? Seriously, Okay just knock the hell. I promise you I will pay for the legal fees, I promise, I promise.”

Trump, characteristically, regrets nothing. On Friday, accepting the endorsement of Ben Carson, a man he once described as “pathological” and likened to a “child molester,” Trump reaffirmed his inclination to meet violence with violence, citing the example of a protester who was “swinging” at the audience.

“And the audience hit back,” Trump said, approvingly. “And that’s what we need a little bit more of.”

Not actually. But it is, I fear, what we will be getting much more of, with Trump at the top of the GOP ticket. He is not a unifier, he is an igniter. The fuse is short and the electorate flammable. The match in Trump’s hands is a dangerous weapon.

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