Donald Trump has used prior Republican debates to great effect, with eye-popping statements about his skills and his rivals' weaknesses to grab headlines, create spectacles, deny other candidates attention and win over voters who are sick of status-quo, milquetoast politicians.
But Tuesday's debate was more substantive and less personality-driven. Fewer candidates participated, for one thing, and there were more opportunities for meaty policy exchanges. That made it harder for Trump to maintain his edge on stage.
During the Fox Business Network debate, Trump still got more time than most of the other candidates at the Milwaukee Theatre. But the businessman-turned-reality-television star spent much of the time on the defense.
In the debate's early moments, two candidates who needed to make a strong impression – former Florida Gov. Jeb Bush and Ohio Gov. John Kasich – double-teamed Trump over his call to deport everyone who is in the country illegally.
"The 11 million people, come on, folks. We all know you can't pick them up and ship them across, back across the border. It's a silly argument. It is not an adult argument. It makes no sense," said Kasich, who is polling in the low single-digits.
Bush, who stumbled badly during the last GOP debate but performed more aggressively Tuesday, argued that Trump's plan was not only impractical but un-American.
"It's not embracing American values. And it would tear communities apart. And it would send a signal that we're not the kind of country that I know America is," Bush said.
"And even having this conversation sends a powerful signal -- they're doing high-fives in the Clinton campaign right now when they hear this. That's the problem with this. We have to win the presidency. And the way you win the presidency is to have practical plans. Lay them out there," he said.
During a clash over whether the U.S. should intervene in Syria, Bush went further, saying Trump was playing children's games at a time of grave danger.
Trump said Russia should "knock the hell" out of Islamic State, also known as ISIS, in Syria and that the U.S. should remain out of the conflict.
"If Putin wants to go and knock the hell out of ISIS, I am all for it, 100%, and I can't understand how anyone can be against it," Trump said.
"They're not doing that," Bush interjected.
"We can't continue to be the policeman of the world," Trump said.
Bush said Trump's views on Russia, Syria and defeating Islamic State were flawed.
"He's absolutely wrong on this. We're not going to be the world's policemen, but we sure as heck better be the world's leader."
Bush continued: "And the idea that it's a good idea for Putin to be in Syria, let ISIS take out Assad and then Putin will take out ISIS? I mean, that's like a board game, that's like playing Monopoly or something. That's not how the real world works."
In prior debates, Trump has relished attacking his rivals on everything from their looks to their perceived energy levels. On the campaign trail recently, he has criticized the pasts of Dr. Ben Carson, who is challenging him for the lead, and Sen. Marco Rubio, who has surged in the polls and is solidly among the second tier of candidates.
But Trump did not challenge either of them during Tuesday's debate. His attacks were limited. He questioned Kasich's record in Ohio while Kasich attacked his immigration policy. And he aimed a zinger at former Hewlett-Packard chief Carly Fiorina: "Why does she keep interrupting everybody?"
The line was met with a chorus of boos.
Lee reported from Milwaukee and Mehta from Los Angeles.
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