The debate ranged from jobs and the economy to gun rights and the best way to fight ISIS, with the most substantive discussion coming from the candidates clashing over taxes and trade. Weeks of negative attack ads and the closeness of the Iowa caucus had tensions high, which came out with Trump battling Cruz, Rubio battling Christie, Cruz battling Rubio, and Bush battling the “back-bench senators.”

But all the candidates were happy to stop their fighting to criticize President Obama and Democratic front-runner Hillary Clinton. No one bothered with Bernie Sanders, other to say that he wouldn’t be nominated, or with Marvin what’s his name.

Fox Business hosted the sixth Republican presidential debate with moderators Neil Cavuto and Maria Bartiromo in North Charleston, S.C. Thursday night. Candidates Donald Trump, Ben Carson, Sen. Marco Rubio, former Florida governor Jeb Bush, Sen. Ted Cruz, Ohio Gov. John Kasich and New Jersey governor Chris Christie all made the main stage. (Sen. Rand Paul didn’t make the cut, but his supporters interrupted the debate once to chant his name in remembrance. Neither did Huckabee, Fiorina, and Santorum.)

Each candidate benefited from having more time to speak, with only seven on stage tonight. The three dominant candidates, the only ones polling in double figures in Iowa — Cruz, Trump and Rubio — got their jabs in, showing that a party united against the status quo of the Obama administration has room for different approaches to returning America to greatness.

Foreign Policy

Foremost in the discussion was how Obama handled Iran’s capture of ten American sailors earlier this week:

“In that State of the Union, President Obama didn’t so much as mention the 10 sailors that had been captured by Iran,” Cruz began. “If I am elected president, no service man or service woman will be forced to be on their knees, and any nation that captures our fighting men will feel the full force and fury of the United States of America.”

Christie agreed, saying he would find a solution to Iran in a stronger military: “We need to rebuild our military, and this president has let it diminish to a point where tinpot dictators like the mullahs in Iran are taking our Navy ships. It is disgraceful, and in a Christie administration, they would know much, much better than to do that.”

Bush was quick to link Hillary Clinton to Obama’s foreign policy. “Hillary Clinton would be a national security disaster. Think about it. She wants to continue down the path of Iran, Benghazi, the Russian reset, Dodd-Frank, all the things that have — that have gone wrong in this country, she would be a national security mess.”

Bush also got in one of the first laugh lines of the night at Clinton’s expense, pointing out that she’s currently under investigation with the FBI. “If she gets elected, her first 100 days, instead of setting an agenda, she might be going back and forth between the White House and the courthouse.”

The North Charleston audience chuckled with Bush but roared with applause for Rubio when he followed up by saying that Clinton “wouldn’t just be a disaster, Hillary Clinton is disqualified from being commander in chief of the United States. Someone who cannot handle intelligence information appropriately cannot be commander in chief and someone who lies to the families of those four victims in Benghazi can never be president of the United States. Ever.”

In stark contrast to the current president, Rubio went on to promise to send any ISIS members captured alive to Guantanamo, where  “we are going to find out everything they know.”

But Carson stumbled when he was asked how he’d tackle ISIS. Instead of outlining a plan, he started talking about electromagnetic pulse (EMP) weapons. Obama is not prepared for terrorists using an EMP to cripple our electrical grid while simultaneously deploying dirty bombs and a cyberattack. That’s true, but he did not explain what he would do about an EMP. He did say, “We have the world’s best military, even though [Obama]’s done everything he can to diminish it. And the fact of the matter is if we give them a mission and we don’t tie their hands behind their back, they can get it accomplished.”

Trump vs. Cruz

The first real fun of the night came in the exchange between the two frontrunners, Trump and Cruz, over the question of whether Cruz is a natural born citizen eligible to become president. Cruz pointed out that in September Trump had said there was nothing to it. “Now since September, the Constitution hasn’t changed. But the poll numbers have. And I recognize, I recognize that Donald is dismayed that his poll numbers are falling in Iowa. But the facts and law here are really quite clear. Under longstanding U.S. law, the child of a U.S. Citizen born abroad is a natural born citizen.”

Trump then suggested that the Democrats would bring a suit over the constitutional question if Cruz won the nomination. “There’s a big question mark on your head. And you can’t do that to the party.”

Cruz’s response was simple: “Listen, I’ve spent my entire life defending the Constitution before the U.S. Supreme Court. And I’ll tell you, I’m not going to be taking legal advice from Donald Trump.”

The two clashed again later, with Cruz going after Trump’s “New York values.” “Let me put this a different way,” Cruz said. “Not a lot of conservatives come out of Manhattan … There are many, many wonderful working men and women in the state of New York. But everyone understands that the values in New York City are socially liberally, pro-abortion, pro-gay marriage, focused around money and the media.”

It must have seemed like a great line to use in South Carolina, but it backfired as Trump responded to applause that those same “New York values” are what shone on September 11th. “New York is a great place, it’s got great people, loving people. When the World Trade Center came down, I saw something that no place on earth could have handled more beautifully, more humanely than New York,” Trump said. “And everybody in the world watched and everybody in the world loved New York and loved New Yorkers. I have to tell you, that was a very insulting statement that Ted made.”

Rubio vs. Christie

“I like Chris Christie,” said Rubio, asked for his take on Christie’s record, and that always comes with a “but.” The two are competing for the ground a little to the left of Cruz. “But,” Rubio continued, “we can not afford to have a president of the United States that supports Common Core. … Chris Christie wrote a check to Planned Parenthood. All I’m saying is our next president has to be someone that undoes the damage Barack Obama has done to this country. It can not be someone that agrees with his agenda.”

Christie hit back, accusing Rubio of hypocrisy since Rubio took issue with Jeb Bush going after him during a previous debate, saying he was only doing so because someone told him it would help him win. “I like Marco too, and two years ago, he called me a conservative reformer that New Jersey needed. That was before he was running against me. Now that he is, he’s changed his tune.”

As they were both saying how disappointed they were with each other, Bush interjected that everyone on that stage would be better than Hillary Clinton. “These attack ads are going to be part of life. Everybody just needs to get used to it. Everybody’s record’s going to be scrutinized, and at the end of the day we need to unite behind the winner so we can defeat Hillary Clinton, because she is a disaster.”

Cruz vs. Rubio

Christie wasn’t the only candidate Rubio had to fight with. Sparks flew later in the debate between  as he defended his work on immigration reform against Cruz, while also unleashing a torrent of research against the Texas senator on immigration.

Cruz hit first, telling Rubio, “You don’t get to say we need to secure the borders and at the same time try to get Barack Obama more authority to allow Middle Eastern refugees coming in when the head of the FBI tells us they cannot vet them to determine if they are ISIS terrorists.”

Rubio hit back: “Ted Cruz, you used to say you supported doubling the number of green cards. Now you say that you are against it. You used to support a 500 percent increase in the number of guest workers. You used to support legalizing people that were here illegally.” “Now you say you are against it. You used to say you were in favor of birth right citizenship, now you say that you are against it.”

The other strong clash between the two came when Rubio made the claim that Cruz’s tax plan includes a VAT (value added tax). Cruz responded, “A critical piece that Marco seems to be missing is that this 16 percent business flat tax enables us to eliminate the corporate income tax. It goes away. It enables us to eliminate the death tax.” Cruz also claimed that his plan would let him abolish the IRS.

Rubio didn’t let it go. “But that’s not an accurate description of the plan. Because, first of all, you may rename the IRS but you are not going to abolish the IRS, because there has to be some agency that’s going to collect your VAT tax.”

Jobs and Tariffs

Kasich was asked what it says about America that a socialist like Bernie Sanders could be the Democratic nominee. While discounting the possibility of Sanders winning (“I know Bernie, and I can promise you he’s not going to be president of the United States”), Kasich explained why people were hurting and defended the American dream. “My father used to say, ‘Johnny, we don’t hate the rich. We just want to be the rich.’ And we just got to make sure that every American has the tools, in K-through-12 and in vocational education, in higher education.”

Trump argued for tariffs against Chinese imports, to which Rubio responded by pointing out that “China doesn’t pay the tariff, the buyer pays the tariff.” Bush piled on, adding that China would retaliate and stop buying American goods in response. “This would be devastating for the economy. We need someone with a steady hand being president of the United States.”

Everyone will agree with that. The challenge for the Republicans is that Hillary Clinton will have a steady hand if she’s elected — if not an iron fist.