MIAMI -- Abandoning the nasty insults of past debates, Donald Trump and his Republican rivals turned Thursday's presidential face-off into a mostly respectful discussion of Social Security, Islam, trade and more. Trump shook his head and declared at one point: "I can't believe how civil it's been up here."
Ted Cruz and Marco Rubio found plenty of areas of difference with Trump, but the candidates largely managed to lay them out without vitriol.
In a lengthy discussion of the threat posed by radicalized Muslims, Trump refused to back away from his recent statement that "Islam hates the West."
Asked if he meant all Muslims, Trump said: "I mean a lot of them" and he wouldn't be "politically correct" by avoiding such statements.
Rubio had a pointed comeback: "I'm not interested in being politically correct. I'm interested in being correct."
The Florida senator noted the Muslims in the U.S. military and buried in Arlington National Cemetery and said the only way to solve the problem of violent extremists is to work with people in the Muslim faith who are not radicals.
Cruz bundled together his criticisms of Trump for what he called simplistic solutions on trade and on Islamic terrorists, saying, "The answer is not to simply yell, 'China: bad, Muslim: bad."
Trump, though, clearly was intent on projecting a less bombastic -- and more presidential -- image.
"We're all in this together," he said early on, sounding more like a conciliator than a provocateur as he strives to unify the party behind his candidacy. "We're going to come up with solutions. We're going to find the answer to things."
Trump's rivals, in a desperate scramble to halt his march to the nomination, gradually ramped up their criticism as the night wore on.
Rubio's overarching message: "I know that a lot of people find appeal in the things Donald says. The problem is presidents can't just say anything they want because it has consequences around the world."
Cruz, eager to cement his position as the party's last best alternative to Trump, had a string of criticisms of the GOP front-runner, too, saying flatly at one point: "His solutions don't work."
Trump refused to take the bait when Cruz repeatedly poked at his foreign policy positions and at one point lumped Trump with Hillary Clinton and John Kerry in supporting the Obama administration's Iran nuclear deal.
Trump's restrained response: "If Ted was listening, he would have heard me say something very similar" to what Cruz had said about the failings of the deal.
In a meaty discussion of Social Security, Cruz and Rubio both said they'd gradually raise the retirement age for younger workers to help stabilize the system and stave off financial disaster for the system.
Trump, in contrast, said he'd do "everything within my power not to touch Social Security, to leave it the way it is."
On that issue, the GOP front-runner couldn't resist taking a dig at the Democrats, saying he'd been watching them intensely on such issues --"even though it's a very, very boring thing to watch" -- and that they weren't doing anything on Social Security.
Cruz said the system was "careening toward insolvency" and it would be irresponsible not to address that. Rubio said Trump's plan to save the system by reducing wouldn't work. Eliminating all fraud and waste "is not enough," he said. "The numbers don't add up."
Each of the candidates had an urgent mission as the GOP debate gave them a last chance to put their case to a televised audience of millions before voters in Florida and four other states dish out delegates next Tuesday. Those elections will go a long way toward determining the outcome of the primary season.
Cruz was seeking to make it a two-man race with Trump. Rubio was out to save his flagging candidacy by energizing voters in his home state of Florida. John Kasich was hoping his above-the-fray strategy would finally pay off.
Trump, for his part, was itching to give his front-runner's campaign a giant thrust toward the nomination by dominating his dwindling cast of rivals.
President Barack Obama, offering political commentary from the sidelines, said earlier in the day the party was going through a "Republican crackup" that had taken on the tone of a "circus." He blamed the GOP itself for fostering the idea "that cooperation or compromise somehow is a betrayal."
Florida is the biggest prize of Tuesday's five-state round of voting, and all 99 of the state's delegates will go to the winner.
In all, 367 Republican delegates will be at stake, with voting also occurring in Illinois, Missouri, North Carolina, Ohio and the Northern Mariana Islands.
Ohio Gov. Kasich, who has tried to stay out of the name-calling, pinned his hopes of survival on bringing home the 66 delegates in his state's winner-take-all primary. He has yet to win anywhere.
In the race for delegates, Trump has 458, Cruz 359, Rubio 151 and Kasich 54. It takes 1,237 to win the Republican nomination for president.
-- Benac reported from Washington. AP Writers Donna Cassata in Washington and Jill Colvin in Fayetteville, North Carolina, contributed to this report.