In First US Republican Debate, 10 Candidates Spar on Immigration, Islamic State, and... Donald Trump

At the opening of the first Republican primary debate on Thursday, the Fox News moderators asked all 10 assembled candidates if they would forswear a third-party challenge and line up behind the eventual GOP nominee.

Donald Trump shrugged. "I will not make the pledge at this time," the billionaire mogul who is now leading in the polls, said. He then joked, "If I'm the nominee, I will pledge I will not run as an independent."

The crowd booed, and it seemed the debate would mirror the dynamic that's so far dominated the campaign: Trump making the headlines, while his opponents play catch-up.

Although Trump did speak for more time than any other candidate — taking up about 11 minutes of the 2 hours debate — the outspoken businessman failed to fully dominate the evening. He did, however, deliver a blustery and, at times, incendiary performance.

One of the more interesting moments came when he suggested that Hillary Clinton was compelled to attend his wedding in 2005 because he had contributed to the Clinton Foundation.

Hillary Clinton at Donald Trump's 2005 wedding (via — TODAY (@TODAYshow)August 7, 2015

"Hillary Clinton, I said be at my wedding, and she came to my wedding," he remarked. "She had no choice because I gave to a foundation."

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The 10 candidates fielded a range of serious and tough debate questions on abortion, economics, gay rights, foreign policy, immigration, and health care. Conspicuously absent from the debate was more than brief mentions of race, income inequality, or women's issues — aside from a segment where all the candidates came together to criticize abortion.

A significant chunk of the debate was spent discussing immigration. Trump took credit for the prominence of the issue in the campaign, telling his opponents, "If it weren't for me you wouldn't be talking about illegal immigration." He also reiterated his claim that the Mexican government was responsible for migrants crossing the border. The US should build a wall across the border, Trump argued; he also suggested the US install a "big door" in the wall for legal immigrants.

Florida Sen. Marco Rubio mocked Trump's proposed wall, noting that the famed Mexican drug lord "El Chapo built a tunnel under the fence." Rubio, who is Cuban-American, has been criticized by the conservative wing of the Republican party for his openness to a version of immigration reform that doesn't require all illegal immigrants to be deported.

Former Florida Gov. Jeb Bush, who is widely considered to be the actual front runner despite Trump's lead in the polls, defended his view that illegal immigrants should be allowed some pathway towards a legal status. "Not amnesty," he said, adding that illegal immigrants should "pay a fine and do many other things to earn right to be here."

Bush also denied reports that he recently called Trump a buffoon, a clown, and an asshole — but he did call out the billionaire businessman for being "divisive."

"We're not going to win by doing what Barack Obama and Hillary Clinton do each and every day: dividing the country, saying, creating a grievance kind of environment," he said, in an oblique attack on Trump's pugnacious campaign.

Trump brushed off the criticism of his unorthodox style as petty. "When you have people that are cutting Christians' heads off, when you have a world, at the border and in so many places… that it's medieval times," he said, "we don't have time for tone — we have to go out and get the job done."

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Ohio Gov. John Kasich, a popular governor in a key battleground state who has yet to gain much national traction, tried to strike a conciliatory tone. "We need to take lessons from Donald Trump," he said. "He's hitting a nerve."

Trump was not as charitable to the lawmakers who joined him on stage, emphasizing over and over again that "politicians are stupid."

In one of the evening's most contentious exchanges, New Jersey Gov. Chris Christie and Kentucky Sen. Rand Paul sparred over privacy issues. Paul is an outspoken critic of the NSA's bulk collection of data and recently mounted a filibuster of the Patriot Act in May to protest the surveillance program.

Christie, a former prosecutor, defended the program on national security grounds. "When you're sitting in a subcommittee just blowing hot air, you can say things like that," Christie said to Paul. "When you are responsible for protecting the lives of the American people, then what you need to do is make sure the system works the way it's supposed to work."

Paul interrupted Christie, saying, "You fundamentally misunderstand the Bill of Rights."

"I'm talking about searches, without warrants, of all American's records," he added. "I don't trust president Obama with our records."

Thursday's debate also included several notable flip-flops.

Paul walked back his previous position that the US — specifically the GOP foreign policy establishment — had some role in nurturing the so-called Islamic State (IS). "ISIS exists and grew stronger because of the hawks in our party," he said in May, using an alternate name for the group. But on Thursday, Paul said that only IS is responsible for its violence.

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Florida Sen. Marco Rubio also appeared to contradict himself. When asked by Fox News moderator Megyn Kelly how he explained his support for exceptions to abortion restrictions in cases of rape and incest, he suggested that she had mischaracterized his position. But Rubio actually co-sponsored the Senate's Pain-Capable Unborn Child Protection Act in 2013, which included those very exceptions.

The debate ended with a softball question pulled from Facebook, that asked if the candidates had "had received a word from God… about what they should take care of first."

"I am blessed to receive the word of God every day," said Texas Sen. Ted Cruz, who announced his candidacy at the evangelical Christian Liberty University and draws much of his support from conservative Christians. Cruz then told the story of how his father's conversion to Christianity prevented his parent's separation.

"God has blessed us," Rubio chimed in. "He's blessed the Republican Party with some very good candidates. The Democrats can't even find one."

Follow Avi Asher-Schapiro on Twitter: @AASchapiro