Updated: January 15, 2016 11:43 AM ET | Originally published: January 15, 2016 11:43 AM EST

Marco Rubio’s rivalry with Chris Christie is escalating, with the first-term Senator from Florida on Friday using the New Jersey Governor’s own statements in support of Supreme Court Justice Sonia Sotomayor against him.

The morning after the first debate of 2016, Rubio told supporters in Derry, N.H., that he would only nominate judges who would promise a strict reading of the Constitution. Rubio said that put him at odds with Christie, one of his chief rivals in New Hampshire.

“One of the things the President is going to do is nominate Supreme Court Justices, maybe as many as four,” Rubio told his crowd. “We need to appoint Supreme Court Justices that understand that the Constitution is not a living, breathing document. It is supposed to be interpreted and applied as originally intended.” Rubio held up Sotomayor as an example of a judge he would not nominate.

Christie has firmly denied he ever backed President Obama’s nomination of Sotomayor to the Supreme Court. “I didn’t voice support for Sonia Sotomayor,” he told CBS’ Face the Nation last weekend. He repeated that during Thursday night’s debate on Fox Business Network. “Let’s set the facts straight. First of all, I never supported Sonia Sotomayor.”

On Friday morning, he was again saying he never backed Sotomayor. “What I said about Sonia Sotomayor was that she deserved an up or down vote, but that she was not the type of Justice I would select if I were President. That’s hardly supporting someone, that’s just saying someone should get an up or down note,” he told MSNBC’s Morning Joe.

Rubio was ready to keep hammering him over Sotomayor, whom Christie has also said would not have been his first choice for a nominee.

“He’s saying I’m not telling the truth. Let me tell you, I have what he said. Let me read it,” Rubio said, pulling a page from his slacks that included Christie’s comments from 2009.

“I support her appointment to the Supreme Court and urge the Senate to keep politics out of the process and confirm her nomination,” Christie was quoted as saying almost seven years ago.

“Sounds like support,” Rubio quipped.

Christie’s campaign brushed off the attack. “This is another disingenuous attack by Rubio and he knows it,” Christie spokeswoman Samantha Smith said.

The attack is set to become a staple of Rubio’s argument against Christie, not necessarily because of its content but because it gives Rubio’s campaign a chance to paint Christie as shifty. As Rubio prepared to deliver the blow, his aides walked over to reporters to make sure they were paying attention.

“I know he likes to argue with people about things, so I thought I’d let him debate himself,” Rubio joked to reporters later.

The sniping between the pair comes as the race in New Hampshire is becoming a contest to be the leading Not-Donald Trump candidate. After yet another debate, that dynamic is playing out anew, with a crowded schedule along the populous New Hampshire-Massachusetts border. Several candidates are set to pass each other as they rush between events south of Manchester, New Hampshire.

Rubio also is stepping up his barbs against fellow Sen. Ted Cruz. “We can’t just elect any Republican,” Rubio said of the Texas Republican.

Speaking of his own crusade against the Democrats’ health care law, Rubio said he has worked to undermine the law through amendments, “not through a 23-hour speech.” He also criticized Cruz’s tax plan, which he said runs counter to the late President Ronald Reagan.

The fight in New Hampshire is set to tilt full-out negative in the weeks ahead. Whereas Iowa’s caucuses value civility and “nice,” New Hampshire voters have a greater appetite for attacks. That helps to explain why Trump remains atop the polls here, and why the ads blanketing television have such a negative tone to them.

“He has been very politically calculating,” Rubio said of Cruz as he left a rally at a Boy’s and Girl’s Club auditorium. “Time and again, he has shown he will change his positions out of political calculation.”

Rubio’s bet is that voters won’t appreciate his choices.

Write to Philip Elliott at philip.elliott@time.com.

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