The two first-term senators – one from Texas and the other from Florida, both the 44-year-old sons of Cuban fathers and both rising conservative stars in the party, made it evidently clear that they see the other as the primary obstacle to securing the nomination if Trump, the current front-runner, falters.
As such, they engaged in an arm-wrestling contest for most of the evening, sparring on Middle Eastern policy, national security and immigration.
Both largely left Trump alone and in fact, when Cruz was invited by debate moderators to attack the real estate mogul, he demurred.
But Cruz had no such restraint when it came to Rubio. Among other criticisms, he accused him of being soft on immigration policy because he helped craft a comprehensive reform measure in the Senate.
“He was fighting to grant amnesty and not to secure the border. I was fighting to secure the border,” Cruz said.
For his part, Rubio charged that Cruz had helped make the United States more vulnerable to a terror attack by supporting a bill that scaled back the reach of U.S. surveillance programs.
“The next time there is attack on an attack on this country, the first thing people are going to want to know is, why didn’t we know about it and why didn’t we stop it?” Rubio said. “And the answer better not be because we didn’t have access to records or information that would have allowed us to identify these killers before they attacked.”
The public spat has been brewing for weeks, with each campaign regularly criticizing the other in the media as Cruz has surged. A recent opinion poll by the Des Moines Register had Cruz leading Trump in Iowa, which holds the nation’s first nominating contest on Feb. 1, 2016. Trump, however, still leads in national polls.
A win by Cruz in Iowa could severely damage Trump’s bid, as the real estate mogul’s political message is largely grounded in his current dominance of opinion polls. It could also hand Cruz the kind of momentum that could derail Rubio’s bid to be the candidate around whom anti-Trump voters rally.
In Las Vegas on Tuesday evening, Rubio articulated a muscular national security outlook, both abroad and at home, defending his support for U.S intervention in Libya in 2011, calling for an increase in the number of U.S. ground troops in Syria and Iraq in the struggle against Islamic State, ramping up military spending, and intensifying .
Cruz, conversely, advocated a more restrained foreign policy, arguing that a bombing campaign against Islamic State would suffice. He contended that the U.S. government had been allowed to collect too much data on Americans in the name of foiling terror attacks.
But both men’s gambits on Tuesday may have had an unintended consequence.
Republican front-runner Donald Trump and former Florida Gov. Jeb Bush went after each other again. After Bush called Trump a “Chaos candidate” earlier in the debate, another back-and-forth began with a question for Trump about his statement that he would go after the families of ISIS terrorists.
Trump reaffirmed his previous statement, saying: “I would be very, very firm with families, and frankly, that will make people think because they might not care much about their lives, but they do care, believe it or not, about their families’ lives.”
Bush then jumped in, saying: “This is another example of the lack of seriousness” of Trump’s candidacy.
He then said that ISIS has declared war on the US, emphasizing the need to have a “serious strategy” to destroy ISIS.
“The idea that that is a solution to this is just crazy,” Bush said. “It makes no sense to suggest this.”
Bush then pointed out that two months ago, Trump said that ISIS was “not our fight.” Trump then cut in to say he never said that.
“He gets his foreign policy experience from the shows,” Bush said.
“Aw, come on,” Trump responded, shaking his head.
Bush continued: “That’s not a serious kind of candidate. We need someone that thinks this through, that can lead our country.”
Trump then implied that Bush is weak.
“We need toughness,” Trump said. “I think that Jeb is a very nice person … but we need tough people. We need toughness.”
Bush cut back in, and then the two talked over each other.
“Am I talking or are you talking, Jeb?” Trump said, to which Bush replied, “I’m talking right now.”
“I know you’re trying to build up your energy, Jeb, but it’s not working very well,” Trump fired back.
“We need a toughness, we need strength,” Trump added. “We’re not respected as a nation anymore, we don’t have that level of respect that we need, and if we don’t get it back fast, we’re just going to go weaker, weaker, and just disintegrate. … We need strength; we don’t have it.”
But Bush didn’t back down.
“Donald, you’re not going to be able to insult your way to the presidency. That’s not going to happen,” he said. “And I do have the strength. Leadership is not about attacking people and disparaging people.”
Trump closed the back-and-forth with this zinger: “With Jeb’s attitude, we will never be great again, that I can tell you. We will never be great again.”