A long-simmering feud between Ted Cruz and Marco Rubio on immigration finally exploded before an audience of millions Tuesday in what ultimately may prove to be a pivotal moment in the race for the Republican presidential nomination.
The fiery exchange between two first-term Cuban-American senators, each vying to break to become the leading challenger to front-runner Donald Trump in the race for the party's nomination, clearly put them on opposite sides of an issue that has in many ways defined the Republican presidential race: Who has a right to become an American?
The issue has become a part of the national security conversation that dominated the year's final Republican presidential debate, further deepening the political dilemma for the party's candidates given the toxicity of anti-immigration positions with many Americans in a general election.
Numerous polls say a majority of Republicans want to deport the estimated 11 million people now living in the country illegally. Numerous polls also show Donald Trump, who calls for building a wall along the border with Mexico and banning Muslims from traveling to the U.S., is the party's runaway presidential front-runner. "I have a very hardline position," he said at Tuesday's debate in Las Vegas. "We have a country or we don't have a country."
But President Barack Obama's last two elections, fueled by the support from minorities, including Hispanics, have some party leaders worried about the party's chances in November.
After being allowed to skate during the first four debates on an issue that may prove to be his biggest vulnerability with conservative Republican primary and caucus voters, Rubio got a direct question about the bipartisan immigration bill that he co-wrote in 2013.
CNN moderator Dana Bash wanted to know whether he still supports a path to citizenship for people in the U.S. illegally.
The Florida senator responded that he's still open to it, but only after enacting tougher border security measures. Since his 2013 bill died in the House, Rubio has distanced himself from it, but he did not disavow it, which some conservatives have said could cost him their votes.
"Here's what we learned in 2013," Rubio said. "The American people don't trust the federal government to enforce our immigration laws, and we will not be able to do anything on immigration until we first prove to the American people that illegal immigration is under control. And we can do that. We know what it takes to do that."
Cruz, who voted against the 2013 bill and began attacking Rubio's immigration record last month, pounced.
Invoking conservative icon Ronald Reagan (who ironically provided a path to citizenship for millions living in America illegally during his term as president), Cruz said Rubio's involvement in the bipartisan "Gang of Eight" that drafted the 2013 bill shows he cannot be trusted given that he campaigned for Senate in 2010 against "amnesty."
"There was a time for choosing, as Reagan put it. Where there was a battle over amnesty and some chose, like Senator Rubio to stand with Barack Obama and [New York Senator] Chuck Schumer and support a massive amnesty plan," the Texas senator said.
Underscoring his move to the right on the issue is Cruz's shift on the expansion of legal immigration, something strongly supported by big business interests who normally bankroll Republican candidates. While Cruz strongly supported legal immigration expansion during the 2013 effort, calling for an expansion of the number of visas for high-skilled foreign workers even more greater than the bill originally proposed, he has since flipped, proposing a sweeping immigration plan last month that seeks to reduce future immigration levels, and associating himself with Trump on the issue.
"We will build a wall that works, and I'll get Donald Trump to pay for it," Cruz said, to laughter and applause from the Republican audience.
Cruz connected the issue of immigration to national security, which dominated the first half of the debate after the recent terrorist attacks in Paris and California. "Border security is national security," he said, arguing that provisions in Rubio's immigration bill would have made it easier for refugees to enter the U.S.
"Ted, you support legalizing people who are in this country illegally," Rubio retorted, a reference to an amendment Cruz proposed to the immigration bill that would have blocked those living in the country illegally from obtaining citizenship but kept a provision in the legislation that let them stay and work in the U.S.
That interpretation has widely been discredited, however. Numerous fact-checkers and conservative opponents of the bill have said Rubio is mischaracterizing an amendment that was intended as a parliamentary "poison pill" to weaken support for the overall bill.
"Marco wants to raise confusion," Cruz said. "It is not accurate what he just said that I supported legalization. Indeed, I led the fight against his legalization and amnesty." He quoted a commentator who said their roles in the debate were as different as "the fireman and the arsonist."
Rubio demanded to know if Cruz is definitively ruling out allowing people now living in the U.S. illegally from ever normalizing their status, a question that the Texan has dodged recently on the campaign trail.
"I have never supported legalization, and I do not intend to support legalization," Cruz said, arguing that millions of people living here illegally have been deported in the past. "We can enforce the laws and if we secure the border, that solves the problem."