WASHINGTON — Chris Christie raised his national profile when he welcomed President Obama to New Jersey in the aftermath of Hurricane Sandy, but that bipartisan display in 2012 is being used against him in 2016.

A super PAC supporting Florida Senator Marco Rubio aired a negative attack ad against Christie that shows him smiling and greeting Obama — and wearing a blue tie, no less. The spot mockingly calls Christie Obama’s “favorite’’ Republican governor.

The 30-second ad that aired Tuesday, with its prancing music and images of Christie and Obama exchanging smiles and greetings, is part of a flurry of increasingly negative ads targeting New Hampshire voters in the month leading to its primary.

“The new year has begun,’’ said former Republican political consultant Patrick Griffin. “And one of the candidates’ New Years resolutions is to redefine the other guy.’’

New Hampshire front-runner Donald Trump so far largely has been spared in over-the-air attacks. Most of the negative ads have targeted Republican candidates vying further down in the polls — Christie, Rubio, former Florida Governor Jeb Bush, and Ohio Governor John Kasich. They are competing to become the mainstream alternative to two insurgent outsiders, Trump and Texas Senator Ted Cruz, and so far none has been able to break out.

“They’re all very tightly clustered in New Hampshire,’’ former New Hampshire GOP chairman Fergus Cullen said. “No one has any significant advantage, but someone’s going to come out on top.’’

The new ad by a Conservative Solutions PAC, a super PAC behind Rubio’s candidacy, attempts to do just that. It presents Christie as a mirror of the president, whose approval rating among Republicans, unsurprisingly, languishes at 11 percent, according to a recent Reuters/Ipsos poll.

“One high-tax, Common Core, liberal energy-loving, Obamacare Medicaid-expanding president is enough,’’ the ad says.

Christie defended his record on Bloomberg this week, noting that Rubio himself has recently been targeted by ads from a super PAC supporting Bush.

“I just wonder what happened to the Marco who so indignantly looked at Jeb Bush and said, ‘I guess someone must have convinced you that going negative against me helps you,’’ the New Jersey governor said. “I guess that same person now must have convinced Marco that going negative against Chris Christie is what he needs to do.’’

Griffin, who has worked on political campaigns in New Hampshire including George H. W. Bush’s and George W. Bush’s presidential bids, said this is just the beginning of the sniping among those candidates.

“The contrast advertising, particularly between Christie, Cruz, Bush, and Rubio, has begun and that is likely to continue for the next several weeks’’ before the Feb. 9 Granite State primary, said Griffin, who is not affiliated with a campaign and works as a corporate media strategist in Boston.

Notably absent are many attacks directed at Trump, who has been polling at the head of the pack since the summer.

Given Trump’s inexplicable ability to deflect political scandals, candidates hesitate to target him, said Dante Scala, a political science professor at the University of New Hampshire.

“There’s a creeping feeling that somehow Trump is operating under a different set of rules than anyone else is, so the typical rules of negative advertising and its effects don’t apply to him,’’ Scala said.

Moreover, candidates are reluctant to antagonize Trump’s large group of supporters, instead hoping another candidate goes after him, Scala said.

“Everyone would agree that Trump’s not a good thing for the party,’’ he said. “But people are reluctant to be the ones to do the dirty work of trying to take down Trump.’’

Negative advertising can sully both the attacker and the attacked. Cruz, Bush, and Rubio, whose unfavorable ratings in New Hampshire, according to a recent Boston Herald poll, are hovering in the 20s and 30s, all could further lose stature in the fray.

In New Hampshire, the negative ads so far haven’t reached a scathing temperature, Scala said.

One ad released by a pro-Bush super PAC favorably compares Bush’s record as governor to Christie’s and Kasich’s. The ad touts Bush’s accomplishments but refrains from directly criticizing the other two candidates.

“So far as negative ads go, it’s — subtle isn’t the word, but mild might be,’’ Scala said.

But as the primary approaches, the number of undecided voters tuning in grows, and the mud-slinging will intensify.

“These ads that are up right now are very gentle compared to what’s coming up a month from now,’’ Cullen said, laughing. “This is just dipping a toe into the water.’’

Follow Globe Correspondent Sophia Bollag on Twitter @SophiaBollag.