Just as Sen. Ted Cruz (R-Texas) soared to the top of numerous polls in Iowa, Sen. Marco Rubio (R-Fla.), one of his rivals for the Republican presidential nomination, called him out as having "isolationist tendencies" when it comes to national security.
On Sunday's "Meet the Press," the Florida senator slammed Cruz for voting against the government's bulk phone data collection program and against defense spending.
"[Cruz] talks tough on some of these issues," Rubio told host Chuck Todd. "For example, he was going to carpet bomb ISIS. But the only budget he's ever voted for in his time in the Senate is a budget that cut defense spending by more than Barack Obama proposes we cut it."
"He voted against the Defense Authorization Act every year that it came up ... I assume that if he voted against it, he would veto it as president," Rubio continued.
"That's the bill that funds our troops. Even the Iron Dome for Israel ... Each time he's had to choose between strong national defense and some of the isolationist tendencies in American politics, he seems to side with the isolationist. And this is an important issue to have a debate over. It's not personal," Rubio said.
In light of recent terrorist attacks, such as those in Paris and San Bernardino, California, Rubio said Cruz's vote to end the surveillance program that recorded cell phone metadata cost the U.S. a "valuable tool" to detect potential terrorist threats.
Weeks ago, it was Cruz who took a punch at Rubio when he accused his fellow Cuban-American of supporting Hillary Clinton's efforts in Libya, which he says aided the rise of Islamic militants.
"Senator Rubio emphatically supported Hillary Clinton in toppling [Muammar] Qaddafi in Libya. I think that made no sense," Cruz said in an interview with Bloomberg Politics.
While Cruz has repeatedly been attacked for his "weak" grasp of foreign policy, he's set himself apart from his Republican counterparts by falling somewhere in the middle between interventionist and isolationist.
"We want to retreat from the world and be isolationist and leave everyone alone, or we've got to be these crazy neo-con invade-every-country-on-earth and send our kids to die in the Middle East," he said at a town hall meeting in Coralville.
"Most people I know don't agree with either one of those," he said. "They think both of those are nuts."
Donald Trump also took a jab at Cruz's performance in the Senate during an interview on "Fox News Sunday."
"You look at the way that he's dealt with the Senate, where he goes in there, frankly like a little bit of a maniac. You're never going to get things done that way."
"I don't think he's got the right temperament," Trump said. "I don't think he's got the right judgment."
The punches against Cruz come days before the candidates face off during CNN's Republican national debate in Las Vegas on Tuesday night.
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