We Just Saw the First Real Fight Between Ted Cruz and Marco Rubio

The Texas senator is honing his attack on his biggest establishment competitor.

Sen. Marco Rubio, left, and Sen. Ted Cruz at the GOP debate in Las Vegas on Dec. 15, 2015.

Photo illustration by Slate. Photos by Justin Sullivan/Getty Images

Substantively, it’s difficult to say there’s anything new in the fifth Republican presidential debate, hosted Tuesday night in Las Vegas by CNN. The topics were terrorism and national security, but the rhetoric was what we’ve seen in past forums.

On the hawkish side, candidates such as Sen. Marco Rubio, Jeb Bush, and Gov. Chris Christie are committed to the basic approach of the George W. Bush years, or at least his first term: confrontation, aggressive rhetoric, and a total willingness to use force, up to and including ground troops. “If our military experts say we need boots on the ground, we should put boots on the ground and recognize that there will be boots on the ground, and they’ll be over here,” explained Ben Carson.

On the other side are Donald Trump, Sen. Ted Cruz, and Sen. Rand Paul, who call for caution in foreign policy and want the United States to shy away from regime change and other foreign interventions outside of direct defense. In the case of Cruz and Trump, that doesn’t preclude action in the Middle East.

The former, in particular, called for carpet-bombing in territories surrounded by ISIS. When Wolf Blitzer pressed Cruz on that point, he refused to back down, although he tried to muddy the waters with a different definition of carpet-bomb than most observers are accustomed to hearing. “You would carpet-bomb where ISIS is, not a city, but the location of the troops,” said Cruz. “The object isn’t to level a city. The object is to kill the ISIS terrorists.”

Again, however, this—the saber-rattling, the calls for “strength,” and the shots at Barack Obama and Hillary Clinton—were boilerplate. The usual accoutrement of a Republican presidential debate. Beyond this, we had the typical bundle of tall claims and wild distoritions—common in debates that fact-checkers will relish in the days ahead.

More interesting than the above were the clashes between candidates. With one exception (which we’ll get to), they didn’t break news. But they didn’t need to. At most, these fights needed to reveal or illustrate something key about the primary. And they did.

The clash between Jeb Bush and Donald Trump shows the extent to which the latter can get peevish when pushed, but the aftermath—in which Trump re-established himself—shows the degree to which the real estate mogul has more political skill than he gets credit for.

More dramatic was the sudden and unvarnished fight between Cruz and Rubio. As soon as he had the chance, the Texas senator went after Rubio—his nearest competitor in most opinion polls—and the Florida senator did the same. But Cruz had an unspoken advantage in the fight: immigration.

Rubio shepherded the “Gang of Eight” comprehensive immigration bill through the Senate but ultimately abandoned it, as conservatives turned in ferocious opposition. Which is to say that Cruz didn’t do much. He just brought up Gang of Eight again, and again, and again. “He’s the weakest of all the candidates on immigration,” said Cruz of Rubio. “He is the one for an open border that is leaving us defenseless. … Marco has had more of an allegiance to Chuck Schumer and to the liberals than he does to conservative policy.”

Kentucky Sen. Rand Paul—who strongly opposes Rubio’s neoconservative approach to foreign policy—took a turn as well, directly tying Rubio to immigration “liberalization.” “On his Gang of Eight bill, he would have liberalized immigration, but he did not—and he steadfastly opposed any new border security requirements for refugees or students,” said Paul. And earlier, Cruz had almost flustered Rubio by directly challenging him on surveillance policy. Between Paul and Cruz, this was the first time Rubio faced serious attacks from other Republicans on his immigration plan. Thus far, it had been left unsaid by everyone. No longer.

Other candidates have scrambled for a strategy to stop Trump. Ted Cruz has one, and it’s working. Others, likewise, have searched for a way to knock Rubio off his game. Cruz has that too. Going forward, we should expect this clash to repeat itself as Cruz continues to hit Rubio on these issues, which are deeply salient to Republican voters.

Between immigration and surveillance, Cruz thinks he has a way to beat Rubio. And if successful, it will pave the path for Cruz to take a strong second place in the race. The question is for Rubio: Can he take the punishment on immigration and survive to build bonds with grassroots conservatives? Or is this the beginning of the attack that will eventually push the young Florida senator from the race?

See more of Slate’s coverage of the GOP primary.