Des Moines, Iowa (CNN) We now know what a Republican presidential debate looks like without Donald Trump -- pretty tame.

The final GOP debate before the Iowa caucuses went on without the party's front-runner Thursday night, and in his absence, the personal attacks, bluster and theatrics that had dominated previous debates were largely gone.

As Trump hosted a rival event for veterans less than three miles away, other leading Republicans clashed along familiar battle lines that included immigration and surveillance, as each tried to make their most forceful case to voters just days away from the Iowa contest. But without Trump on stage, there were few breakout moments that are likely to change the course of the race.

The evening kicked off with a tribute to what Fox News moderator Megyn Kelly called the "elephant not in the room."

"Let me say, I'm a maniac, and everyone on this stage is stupid, fat and ugly and Ben, you're a terrible surgeon," said Texas Sen. Ted Cruz, Trump's closest rival in the Hawkeye State. "Now that we've gotten the Donald Trump portion out of the way..."

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Marco Rubio said the 2016 presidential campaign is "not about Donald Trump."

"He's an entertaining guy, he's the greatest show on earth," the Florida senator said, adding that the party should focus on preventing Democrat Hillary Clinton from winning the White House.

Jeb Bush, who has grown increasingly combative with Trump over the months, joked that he wished the real estate mogul was there. He also appeared to take a swipe at his rivals on stage for not taking on Trump as aggressively as he has.

"I kind of miss Donald Trump. He was a little teddy bear to me," Bush said. "Everybody else was in the witness protection program when I went after him."

But beyond these initial remarks, Trump was missing from the conversation for most of the two-hour debate. Instead, seven of his competitors went head-to-head on policy, as they jockeyed to prove their conservatism and preparedness to run the country.

"The exchanges were much more civil. You didn't have any gratuitous insults," Cruz said on Fox News after the conclusion of the debate.

Policy clash

Not for the first time, immigration drew some of the sharpest clashes.

Rubio, who co-sponsored the so-called "Gang of Eight" bipartisan immigration reform bill, was on the defensive on one of his most vulnerable issues.

"I do not support blanket amnesty," he said.

Bush turned to his fellow Floridian and said he was "confused" to hear Rubio say this, as he accused the senator of changing his position for political expediency.

"He cut and run because it wasn't popular among conservatives, I guess," Bush said.

Cruz also defended his conservative credentials on immigration. He said an amendment he proposed during the Senate's immigration debate made clear that "anyone here illegally is permanently ineligible for citizenship."

"My friend Sen. Rubio stood with Barack Obama, Harry Reid and Chuck Schumer" and supported amnesty, Cruz said.

Paul jumped in by calling Cruz's statements on immigration "insulting" and said Cruz had no place accusing his rivals of being for amnesty. Rubio was quick to join in.

"This is the lie that Ted's campaign is built on," Rubio said. "He's the most conservative guy and everyone else is a 'RINO.'"

Christie — who is counting on a solid performance in New Hampshire -- seized on the moment to deliver a powerful rebuke of his rivals. He called Cruz and Rubio products of Washington skilled at making procedural arguments that are inconsequential to voters, in a moment clearly aimed at setting himself apart as a Washington outsider.

"This is why you need to send someone from outside of Washington to Washington," the New Jersey governor said. "I feel like I need a Washington-to-English converter."

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The candidates also butted heads on surveillance and national security. Cruz, in particular, was hit for his vote on NSA reform.

Christie, who has been critical of Cruz's vote to end the NSA's bulk data collection program, said the senator's vote "made the country less safe."

Rand Paul also joined in, accusing Cruz of flip-flopping. "Ted said he was for NSA reform, but then he told Marco Rubio, no, no, no, I voted for the bill because I'm for the government collecting 100 percent of your cell phone records," the Kentucky senator said. "I don't think Ted can have it both ways."

Unexpected curveball

Trump threw an unexpected curveball into the 2016 campaign this week when he declared that he would boycott the debate amid an escalating feud with Fox News.

The decision came amid a feud with Fox News after Trump questioned whether moderator Megyn Kelly would treat him fairly at the debate.

In an interview with CNN's Brianna Keilar on Thursday, Trump said Fox News "apologized" to him for a mocking statement the television network issued two days before the debate. While the network "could not have been nicer" as it tried to woo him back into attending the debate, Trump said he would stick to his plan of holding the event for veterans.

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"I was treated very unfairly by Fox. Since then they've been excellent, they've been very nice, but it's too late," he said in the interview aboard his private plane.

A Fox News spokesperson said Roger Ailes, the network's chief executive, had "three brief conversations" with Trump on Thursday.

"In the course of those conversations, we acknowledged his concerns about a satirical observation we made in order to quell the attacks on Megyn Kelly, and prevent her from being smeared any further," the spokesperson said.

At his competing event, Trump said he raised more than $6 million for veterans in a single day. He dismissed any notion that his absences from the debate would hurt him with voters.

"When you're treated badly you have to stick up for your rights," Trump said. "And that's what our country has to do."

Undercard

Trump's boycott was also a topic of conversation at an earlier undercard debate featuring four lower-polling candidates -- Carly Fiorina, Mike Huckabee, Rick Santorum and Jim Gilmore. Santorum quickly expressed deep frustration with the drama surrounding Trump.

"The entire lead-up to this debate was about whether Donald Trump was going to show up to the next debate," Santorum said. "The people of Iowa ... care a lot about the issues. They care about who's going to be the leader of the free world."

Santorum and Huckabee, two previous winners of the Iowa caucuses, attended Trump's veterans event after the debate.

Gilmore, who has not qualified for most undercard debates, mocked Trump's rival event, as he called himself "the only veteran" running for president this cycle.

"I'm not going to any Donald Trump event over across town on some sort of faux veteran sort of issue," Gilmore said.

He appeared to relish his time in the spotlight, taking issue on several occasions with how many questions he was being asked by the moderators.

"Did you miss me? Did you skip me?" Gilmore blurted out when a question went to Huckabee.