AP
Marco Rubio and Ted Cruz.
Fox moderator Maria Bartiromo said the US is on track to issue more green cards and asked why Rubio was supporting opening borders to foreign workers when Americans are having a hard-enough time getting jobs.
"First and foremost, this issue has to be now ... keeping America safe," Rubio said. "There is a radical jihadist group that is manipulating our immigration system. And not just green cards. They're recruiting people to enter this country as doctors, as engineers, and even fiancees."
When Bartiromo asked if Rubio's thinking has changed, he said the issue of immigration today is "dramatically different" than it was two years ago. (Back in 2013, after the Boston Marathon bombing, he argued it shouldn't affect progress on immigration reform.)
Rubio then argued that ISIS attempts to exploit the US' legal immigration system and said they must be prevented from getting into the country.
Cruz then cut in and said that "radical Islamic terrorism was not invented 24 months ago."
He also said blasted Rubio for the 2013 immigration bill Rubio co-authored that Cruz said "expanded Barack Obama's power to let in Syrian refugees."
Cruz then said the Senate voted a few weeks ago to suspend refugees from Middle Eastern countries.
"I voted 'yes' to suspend that, Marco voted on the other side," Cruz said. "So you don't get to say, 'We need to secure the borders' and at the same time try to give Barack Obama more authority to allow more refugees coming in."
Rubio then jumped in and threw a kitchen sink of attacks at Cruz - over everything from immigration to Cruz's alleged shifting on his feelings about former NSA contractor Edward Snowden:
"Ted Cruz, you used to say you supported doubling the number of green cards. Now you say that you're against it. You used to support a 500% increase in the number of guest workers. Now you say that you're against it. You used to support legalizing people that were here illegally. Now you say that you're against it. You used to say that you were in favor of birthright citizenship. Now you say that you are against it. And by the way, it's not just on immigration. You used to support [Trade Promotion Authority]. Now you say you're against it. I saw you on the Senate floor flip your vote on crop insurance because they told you it would help you in Iowa. And last week we all saw you flip your vote on ethanol in Iowa for the same reason. That is not consistent conservatism. That is political calculation."
Rubio closed by saying that every time there is a defense bill in the Senate, three people team up to vote against it: Vermont Sen. Bernie Sanders (I-Vermont), Sen. Rand Paul (R-Kentucky), and Cruz.
Cruz demanded time to respond, telling Rubio, "I appreciate you dumping your oppo research folder."
"At least half of the things Marco said are flat-out false," Cruz said. "They're absolutely false."
On immigration, Cruz said that Rubio had stood with Sen. Chuck Schumer (D-New York) and Obama - and that he was on the other side. He added that Rubio stood today saying he supports legalization and citizenship for 12 million immigrants living in the country unlawfully, while Cruz opposes legalization and citizenship.
Cruz ended with this: "And by the way, the attack he keeps throwing out, on the military budget, Marco knows full well I voted for his amendment to increase military spending to $697 billion. What he said - and he said it in the last debate - it's simply not true."