It took nearly 90 minutes, but CNN debate moderator Jake Tapper eventually asked Donald Trump to respond to a violence incident caught on tape at a rally in North Carolina — a black protester punched in the face by an elderly white man, who was belatedly charged with assault. For the past few months, Trump's rallies had begun with a message asking voters not to rough up protesters. But had Trump "done anything to create a tone where this kind of violence would be encouraged?" Unsurprisingly, the mogul-turned-candidate said he hadn't.

"There is some anger," said Trump. "There's also great love for the country."

Jeers and violence erupted between Donald Trump supporters and protesters at the Republican frontrunner's rally in Fayetteville, N.C., on March 9. (Jenny Starrs/The Washington Post)

It might have been a chance for Trump's rivals to criticize the front-runner over incidents that dominated cable news all day, both the North Carolina punch-up and an off-camera incident in which Trump campaign manager Corey Lewandowski allegedly shoved Breitbart reporter Michelle Fields.

None of them did so.

"I think for every one of us, we need to show respect to the people. We need to remember who it is we're working for," said Sen. Ted Cruz (R-Tex.). "You know, we've seen for seven years a president who believes he's above the law, who behaves like an emperor, who it is all about him and he forgot that he's working for the American people. And let me — let me ask, turn the camera our here. How many of y'all feel disrespected by Washington?"

When some audience members cheered, Cruz said confidently that "the frustration that is boiling over" came from people feeling disrespected.

But John McGraw, the man arrested for assault in North Carolina, did not give reporters the impression of a man driven to temporarily over-reaction by big government. Interviewed by Inside Edition, he expressed no remorese.

"Yes, he deserved it," McGraw said. "The next time we see him, we might have to kill him. We don't know who he is. He might be with a terrorist organization."

None of Trump's rivals opted to condemn that action — or condemn Trump for anything he'd done to incite it.

"I worry about the violence at a rally period," said Gov. John Kasich (R-Ohio). "I mean, it's — you know, elections are important but the unity of this country really matters. Jake, here's what I think is happening. There are people out there who are worried about their jobs."

Sen. Marco Rubio (R-Fla.) ran even further away from the context, opting — like Trump — to immediately change the subject from vigilante violence at a rally to how law enforcement officers "deserve our respect" every day.

"On the issue of anger: Yes, people are angry," said Rubio. "Of course they're angry. Every institution in America has been failing us for the better part of 20 years or 30 years."

The "violence" round of the debate was in sync with the rest of the night, as candidates passed on chance after chance to criticize Trump. (Cruz was often the exception, but he said little that was not recycled from stump speeches.) The debate ended with none of Trump's rivals criticizing him for incitement, or for expressly criticizing the violence that had swallowed a day of news — and more directly, injured a peaceful protester.