Coral Gables, Fla. - This may be the debut of the general election Donald Trump. The frontrunner is endeavoring to present himself as more presidential - and decidedly more low-key - version of himself. And with clear leads in national polls, his advisers might see a chance to pivot toward the November vote.
As my colleague James Salzer put it, he's playing like the Atlanta Braves of the late 1990s with a 20-game lead in August. Which is to say, he's playing it safe.
The problem with a more subdued Trump is two-fold. His most fervent supporters love the say-anything bombastic candidate who enthralls crowds. And when that Trump fails to show up, he opens himself to the "low energy" critique that he used, to great effect, to demolish Jeb Bush during his failed bid.
It didn't seem easy for Trump to bite his tongue. At times, he looked physically uncomfortable holding back as his opponents grabbed screentime. And yet, when Ted Cruz claimed to be the only candidate who could defeat Trump, the billionaire used his response partly to cast his attention toward the Democratic frontrunner.
"I beat him in 13 contests. I have about 1.6 million votes in this primary season. More votes than Ted," he said. "I beat Hillary in many of the polls taken ... and believe me, I haven't even started on her yet."
Here's a running blog of key developments:
Updated 10:30 p.m.: Amid increasing violence at some of Donald Trump's raucous rallies, the billionaire was asked whether his tone encourages his supporters to cause physical harm to protesters.
"I hope not. I truly hope not. We have 25, 30,000 people. They come with tremendous passion and love for our country ... When they see what's going on in this country, they have anger that's unbelievable," he said.
He was read multiple comments he's made urging his supporters to bottle up demonstrators. The candidate has reminisced about the "good ole days" when demonstrators were roughed up, and once said he'd like to punch one in the face.
"We have some protesters that are bad dudes. They have done really bad things ... If they're going to be taken out, we have to run something" he said, trailing off.
Updated 10:05 p.m.: In one of the most interesting exchanges of the debate, the Republican candidates outlined starkly different views on Cuba policy - hitting close to home for the South Florida audience.
Updated 9:55 p.m.: When Donald Trump was asked bluntly what he meant by saying that Islam "hates us," he didn't back down.
"I mean a lot of them," he said.
Marco Rubio offered a sharp response:
"He says what people wish they could say. The problem is presidents can't just say what they want," he said.
When Trump said he wasn't afraid to be politically incorrect, Rubio had one of the best lines of the night.
"I'm not interested in being politically correct," he said. "I'm interested in being correct."
Updated 9:33 p.m.: Donald Trump gives himself a little pat on the back after promising a gentler Republican debate.
"So far, I cannot believe how civil it's been up here."
Updated 9:20 p.m.: Even Donald Trump's acknowledgement that retired neurosurgeon Ben Carson was endorsing his campaign didn't come across in his usual boastful way.
"By the way," he mentioned almost as an aside, Carson will publicly announce his support on Friday.
Updated 9:15 p.m.: In the opening minutes of the last few Republican debates, frontrunner Donald Trump, Florida Sen. Marco Rubio and Texas Sen. Ted Cruz might as well have been in a boxing ring.
This time, though, the first 15 minutes of the debate had a markedly different feel.
Posted: 8:53 p.m.: For a glimpse at how transformation the Republican presidential race has been this year, look no further than the extraordinary comments that GOP national chair Reince Priebus made Thursday in opening another high-stakes debate.
The party will back whoever emerges the nominee "100 percent, there's no question about that," Priebus said to scattered applause, adding: "Can you at least agree with me that these four gentlemen will be better than Hillary Clinton or a socialist?"
That Priebus even had to say the party elite would back its nominee at this late stage in the race is remarkable. And it underscores, yet again, the tension over the forces gathering within the party aimed at stopping frontrunner Donald Trump before he gets an insurmountable edge in the race for delegates.