GREENVILLE, South Carolina — Sen. Ted Cruz (R-TX) smashed Sen. Marco Rubio (R-FL), one of his 2016 GOP presidential rivals, for breaking his promise to the voters who elected him that he would not support amnesty for illegal aliens.

The aggressive comments from Cruz about came during the last part of his lengthy exclusive interview with Breitbart News in his Greenville campaign office here last Monday.

They represent one of the most unreported stories in the 2016 presidential cycle: Rubio’s work on not just the “Gang of Eight” amnesty bill, but now the recently discovered unlimited mass Muslim-migration provisions in his so-called “I-Squared” bill recently uncovered by a Breitbart News investigation from reporter Julia Hahn.

“Border security is national security,” Cruz told Breitbart News in the interview when asked what separates him and Rubio when it comes to national security. “No candidate who has advocated amnesty, who has advocated leaving our border unsecured, who has advocated giving President [Barack] Obama the ability to bring in tens of thousands of Syrian refugees with no background checks can plausibly claim to be an effective leader on national security,” he said.

“An unsecured border and millions coming into this country illegally with the promise of amnesty—with no background checks whatsoever—is fundamentally inconsistent with keeping America safe,” he said. “Each of us in public office makes a choice, makes a choice of where you stand.”

It remains to be seen if CNN’s Wolf Blitzer, the moderator of Tuesday night’s debate in Las Vegas, will ask Rubio about his Gang of Eight amnesty bill.

Up until this time, not one debate moderator–from The Fox News Channel to CNN to CNBC to the Fox Business Channel–has asked Rubio about his only legislative accomplishment other than being the 60th vote for Obamatrade’s Trade Promotion Authority.

But Cruz, in this interview, noted that Rubio’s “Gang of Eight” amnesty bill—which divided the two presidential candidates back in 2013—was something Ronald Reagan, the former president of the United States, would have called a “time for choosing.”

“In 2013, the battle of the Gang of Eight was as Reagan would say a ‘time for choosing’ where every member of Congress had the ability to decide ‘who am I and what are my core principles?’” Cruz told Breitbart News. He continued:

A great many of us, including me and including Sen. Rubio, had promised the men and women who elected us that if you sent us to the Senate we would fight tooth and nail against amnesty. In 2013, I made the decision to honor that promise. Sen. Rubio made a different decision. He chose to stand with Barack Obama and Chuck Schumer and the establishment Republicans and push the most massive amnesty program in the history of our country—push legislation that would not secure the border, push legislation that would grant citizenship to over 12 million people here illegally, push legislation that would give President Obama a blank check for admitting Middle Eastern refugees with no background checks. I made a very different decision. I made a decision to stand with Jeff Sessions, with Steve King and with the American people against amnesty, against leaving our borders unsecured and against driving down the wages for millions of working men and women who have been trapped in economic stagnation for two decades now. That is one major divide.

Cruz is correct in his criticism that Rubio violated the promise he made to Floridians. In fact, back when he was running for Senate in 2010, he explicitly stated multiple times he wouldn’t back an amnesty.

“In fact, I’m strongly against amnesty… So I am not and I will never support – never have and never will support — any effort to grant blanket, legalization amnesty to folks who have entered or stayed in this country illegally,” Rubio said in one such instance in the 2010 election against former Gov. Charlie Crist, who also flip-flopped on immigration.

Cruz added, when asked later in the interview with Breitbart News, that Rubio’s views on immigration and support for open borders are outside the mainstream views across the United States.

Rubio, who still supports everything that was in his amnesty bill with Sen. Chuck Schumer (D-NY)—the future Democratic leader of the U.S. Senate—backs massive increases in immigration levels to the United States, and still backs citizenship for illegal aliens.

Cruz, meanwhile, doesn’t back amnesty for illegal aliens—he refuses to have any establishment media created debate about what to do with illegal aliens until the border is finally secured, the immigration laws of the nation are enforced and the legal immigration system is back under control—and wants to look out for the average American citizen rather than foreigners when it comes to immigration policy and other policy matters like trade, traditional marriage and more.

“It is not a question of moderation. It is a question of whether you stand with the Washington elites or the working men and women of America,” Cruz said. He continued:

So on the question of amnesty, Sen. Rubio stands with the Washington elites—I stand with the working men and women of America. On TPA and TPP, Sen. Rubio stands with the Washington elites—I stand with the working men and women of America. On marriage—and deeming the Supreme Court’s decision, as Sen. Rubio put it, ‘the law of the land,’—Sen. Rubio stands with the Washington elites and I stand with the men and women of America. I understand that five unelected lawyers have no authority whatsoever to tear down the marriage laws of the United States.

Cruz concluded by making the point that nominating a big government liberal Republican like Rubio is a surefire way for Republicans to lose general elections—just like they did with Bob Dole in 1996, John McCain in 2008 and Mitt Romney and 2012. It’s only a populist like him, Cruz argues, that can turn out enough voters to beat likely Democratic nominee Hillary Clinton in November 2016.

“The Washington elites through the mouthpiece of the mainstream media that the only way to win the general election is to embrace the big money policies of Washington. We have tried that recipe,” Cruz said.

We tried it with Bob Dole, with John McCain, with Mitt Romney. And every time we follow that policy prescription, millions of working men and women stay home and we lose. The only way to beat Hillary Clinton is to run a populist campaign of working men and women who want to believe again in the promise of America and to run it against the bipartisan corruption of Washington that Hillary embodies.

“If we nominate a candidate who has stood with the Washington elites against the working men and women of America, we will not be able to win the general election,” Cruz said.