Republican frontrunner Donald Trump took the unprecedented step of skipping the Jan. 28 presidential debate — a particularly important debate as it is the final one before Iowa caucuses take place Monday, Feb. 1.

With Trump off the main stage, Texas Senator Ted Cruz, Florida Senator Marco Rubio, retired neurosurgeon Ben Carson, former Florida Governor Jeb Bush, New Jersey Governor Chris Christie, Ohio Governor John Kasich and Kentucky Senator Rand Paul delved deeper into policy-related issues.

Immigration proved to be one of the major areas of contentious debate between the candidates. But before the discussion on immigration continued, one candidate addressed the major elephant of the room of Trump's absence.

The spotlight of the debate appeared to shine Cruz, who trails Trump in Iowa by 7 percent, according to a recent NBC/Wall Street Journal poll. Though Cruz was at the center of the stage in the wake of Trump's decision not to attend, he could not help but poke fun at his absent competitor, who held an event for veterans in Des Moines instead of attending the debate.

“I’m a maniac and everyone on this stage is stupid, fat and ugly and Ben (Carson), you're a terrible surgeon,” Cruz said jokingly before thanking the candidates for respecting Iowa voters by attending the debate. "Now that we've gotten the Donald Trump portion out of the way, I want to thank everyone here for showing the men and women of Iowa the respect to show up."

From that point forward, Fox News moderated a policy-focused debate with immigration playing a prominent role.

Rubio attacked Cruz on immigration, saying he was inconsistent on his views on amnesty. After Fox News moderator Megyn Kelly showed a 2013 video of Cruz siding with Rubio in attempting to add an amendment to the immigration reform bill, Rubio lashed out at the Texas senator for the opposing stance he has today.

“This is the lie that Ted’s campaign is built on, “ Rubio said. “The truth is, Ted, throughout this election, you’ve been willing to do or say anything in order to win votes."

Paul also chimed in, adding that Cruz is an opportunist because he supported amnesty for illegal immigrants in 2013 but no longer does. Paul argued Cruz has an "authenticity problem."

The focus of the immigration issue then turned over to Rubio and Bush as Bush attacked him for his flip-flop views as well. 

While the two Floridians backed each other on denouncing “blanket legalization amnesty” to illegal immigrants in 2013, Bush said Rubio's co-sponorship of the Gang of Eight bill created a pathway to citizenship. Bush claimed Rubio's idea of a pathway to citizenship contradicted his earlier statements.

“I'm kind of confused because he was the sponsor of the Gang of Eight bill that did require a bunch of thresholds but ultimately allowed for citizenship over an extended period of time," Bush said. "I mean, that's a fact. Then he cut and run because it wasn't popular amongst conservatives, I guess.”

Christie used this opportunity to make his case that Washington, D.C. needs an outsider like himself to make substantive change. Christie said he would not deceive or confuse the American people like his competitors. He also noted governors are more accountable than members of Congress.

“Ted can change his mind," Christie said. "Marco can change his mind. It's perfectly legal in this country to change your mind. But when you’re a governor, you have to admit it and can’t hide behind parliamentary tricks. That’s the difference and that’s the kind of leadership we need in the White House."

Carson also employed the same argument that he had the advantage of not being an establishment Republican.

“I’m the only one on this stage with no political title," Carson said. “You’re not going to hear a lot of polished political speech from me. But you will hear the truth, and I don’t think you have to be a politician to tell the truth.”

If there was one universal point of agreement during the debate, it would likely be the open hostility expressed against former Secretary of State and Democratic Party presidential nominee Hillary Clinton. 

Many said Clinton was the greatest threat to rebuilding the nation and securing the White House. Paul called her an ineffective champion for women’s rights because of her support for her husband Bill, who had an affair during his presidency. 

Rubio added Clinton was disqualified for office because of her role in the Benghazi attacks. But Christie was perhaps the most aggressive, citing his prosecutor experience as the reason he would be the best-suited candidate to hold her accountable for her actions.

“There is no one on this stage better prepared to prosecute the case against Hillary Clinton than I am,” Christie said. “I will be ready. I will take her on, and when I take her on I guarantee you one thing, she will never get within 10 miles of the White House. The days for the Clintons in public housing are over.”