CLEVELAND -- Donald Trump continued to dominate the Republican presidential contest in Thursday's first primary debate, using his trademark bluster to attack rivals and defend his many controversial statements while deflecting questions about past campaign contributions and his own business record.
"I cannot say. I have to respect the person ... if it’s not me."'
Nine other candidates sharing the stage with Trump struggled -- with varying degrees of success -- to break through. Ohio Gov. John Kasich, buoyed by a supportive home state crowd, grabbed the mantle of sensible centrist while Kentucky Sen. Rand Paul sounded angry and defensive. Former Florida Gov. Jeb Bush survived a barrage of pointed questions.
Trump, a billionaire real estate mogul and former reality show host, got the debate off to a feisty start, refusing to rule out running as an independent in the general election if he fails to capture the GOP nomination.
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Fox News host Bret Baier launched the debate by asking the 10 candidates to raise a hand if they couldn't promise to endorse the Republican standard bearer. Trump was the only one to do so, drawing gasps, boos and cheers inside the Quicken Loans Arena.
"I cannot say. I have to respect the person ... if it’s not me," Trump said, teasing the possibility of a third-party run.
Trump, the top-polling GOP candidate, was the debate's headliner, standing alongside contenders who had place among the top 10 in the crowded field in several national polls. Earlier Thursday, Fox hosted the remaining seven candidates in a forum.
Over the course of the two-hour debate, Trump contended anew that many of the Mexican immigrants who come over the southern border into the U.S. have criminal motivations, saying he had been told that by "border control people." He also boasted that his political contributions over the years had pushed elected officials -- including Hillary Clinton, when she represented New York in the Senate -- to do as he asked.
"I give to everybody. When they call, I give. And you know what? When I need something from them, two years later, three years later, I call them, they are there for me," Trump said, adding, "With Hillary Clinton, I said be at my wedding, and she came to my wedding. You know why? She had no choice, because I gave."
Trump's refusal to rule out an independent run drew an immediate and sharp rebuke from Kentucky Sen. Rand Paul, who accused Trump of "hedging his bets."
"He's used to buying politicians," Paul said of Trump -- presumably a reference to Trump's past campaign contributions to the Clinton Foundation and Hillary Clinton's Senate campaigns.
Trump was also questioned about past comments he'd made about women. Host Megyn Kelly noted he had referred to various women as "fat pigs, dogs, slobs and disgusting animals."
"Only Rosie O'Donnell," Trump replied, adding he didn't have time for "total political correctness."
Trump was joined onstage by Paul, Bush, Wisconsin Gov. Scott Walker, former Arkansas Gov. Mike Huckabee, Carson, Rubio, Texas Sen. Ted Cruz, New Jersey Gov. Chris Christie and Kasich.
Kasich, who has been in the campaign only a few weeks and has largely tried to steer to the center, acknowledged that Trump was "hitting a nerve" among voters, particularly on illegal immigration, and warned against ruling him out as a candidate.
Trump wasn't the only candidate to generate fireworks. A heated argument broke out between longtime antagonists Paul and Christie over National Security Agency surveillance practices. Christie, a defender of the practices, said his experience as New Jersey's U.S. attorney in the wake of the 9/11 terror attacks gave him firsthand experience with terror threats. Paul, a libertarian critical of surveillance, insisted the government should obtain a warrant first.
"Senator, you know, when you're sitting in a subcommittee just blowing hot air about this you can say things like that," Christie said. Paul retaliated later, reminding viewers that Christie had worked closely with President Obama after Hurricane Sandy ravaged the New Jersey coast in 2012.
"I know you gave him a big hug, and if you want to give him a big hug again, go ahead," Paul said.
Bush, the field's presumed front-runner before the Trump surge, was pushed to defend his views on Common Core education policies and the Iraq War launched by his brother, former President George W. Bush.
"Knowing what we know, with faulty intelligence and not having security be the first priority when we invaded, it was a mistake. I wouldn’t have gone in," Bush said.
Bush pushed back gently against Trump, saying his divisive rhetoric would alienate voters in a general election.
"I want to win," Bush said, suggesting Trump had created a "grievance environment."
The candidates generally agreed on most social issues, decrying Planned Parenthood and legal abortion and vowing to protect religious liberty. Kasich drew a bit of contrast with others in the field on same sex marriage, saying he had recently attended the wedding of a gay friend.