CNN  — 

Second-tier Republican presidential candidates blasted Donald Trump as unfit to be president and feuded over Kentucky county clerk Kim Davis’s stand against same-sex marriage in a spirited debate on CNN Wednesday.

The four lowest-ranking GOP White House hopefuls, South Carolina Sen. Lindsey Graham, ex-New York Governor George Pataki, former Sen. Rick Santorum and Louisiana Gov. Bobby Jindal also squabbled over taxes, immigration, national security and the minimum wage.

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Right from the top of the debate at the Reagan presidential library, the candidates unloaded on Trump, the Republican front-runner, who was expected to face intense attacks in a later showdown between the 11 candidates at the top of national opinion polls.

Jindal said that Democrats were gifting the election to the GOP with front-runner Hillary Clinton’s misfiring campaign, but he warned that the best way to hand it back would be to nominate Trump.

“He’ll implode in the general election or if, God forbid, if he were in the White House, we have no idea what he would do,” Jindal said.

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Pataki warned Trump was “unfit to be the president of the United States or the Republican nominee,” saying that the billionaire had once promised to make Atlantic City great, just as he now vows to make America great, but had instead turned the coastal resort into an economic nightmare.

Graham, who at times seemed to seize the initiative in the debate, drove home his belief that only he, after decades in the Air Force and 35 trips to Iraq and Afghanistan, is qualified to be commander-in-chief.

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“President Obama is making a mess of the world,” he said, and warned it would be wrong to choose another “novice” to be commander-in-chief, arguing Obama’s inaction had provoked a humanitarian crisis in Syria.

“How does President Obama sleep at night? Look what you let happen on your watch,” Graham said.

Pataki and Santorum, meanwhile, haggled over the fate of Davis, who went to jail for several days rather than issue marriage licenses to same-sex couples.

The former New York governor said that he would have fired Davis over her refusal to honor a Supreme Court decision opening the way to nationwide gay marriage, despite the fact she has emerged as a heroine among conservative voters.

Jindal objected: “We need a president who’s going to fight a court that is abusive, that has superseded their authority.”

Pataki hit back.

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“Wow. You know, we’re going to have a president who defies the Supreme Court because they don’t agree” he said, arguing that the Constitution requires legislators to act if previous laws were struck down.

But while the four candidates traded barbs over numerous issues, there were also calls for the GOP to focus on the ultimate prize of taking back the White House to ensure there would not be a liberal majority on the court if a Democratic candidate became president.

“If it is Hillary Clinton, Joe Biden or Bernie Sanders, they’re going to pick people we’re going to disagree with all the time,” Graham said in reference to Supreme Court nominations. “Please understand that we have to win this election.”

Each candidate set out to plow his own route to better poll numbers in the debate. Graham narrowed in on national security, while Jindal eviscerated the Republican establishment in Washington, complaining that GOP leaders had failed to overturn Obamacare despite congressional majorities. Pataki said he would be the only candidate who could win support among Democrats and apparently also had an eye on independent voters who can be important in the New Hampshire Primary. Santorum, meanwhile, sought to court the social conservative voters who helped him win the Iowa caucuses in 2012.

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Graham and Santorum also dueled over immigration. Santorum said he would start by reinforcing the southern U.S. border while ordering millions of people who had overstayed their visas to leave. But Graham countered that any Republicans who alienated increasingly important Latino voters were doomed to lose the White House.

“Who won Hispanics?” he asked, referring to previous elections. “In my world, Hispanics are Americans.”

In an intense 75-minute debate among bottom-tier candidates who are desperate just to keep their long-shot White House challenges alive and to try to somehow leap into the top echelon of candidates, there wasn’t much light relief.

Graham repeatedly warned that the failure of the United States to destroy ISIS in Syria and Iraq would lead to terrorist attacks on U.S. soil.

But despite his dark world view, Graham did have a few funny lines – in one case, for example, he recalled that Reagan used to share cocktails with Democratic House Speaker Tip O’Neill when he was president.

He said the first thing he would do in the White House would be to reach out to Democrats to try to break Washington’s legislative logjam, saying “we are going to drink more.”