In an effort to bring down surging front-runner Newt Gingrich, the Romney campaign has deployed a very strange choice of attack dog: former White House chief of staff John Sununu.

Sununu is everywhere these days. On a campaign conference call with reporters last week, he accused Gingrich of “a pattern of anti-principled actions that really irritated his own leadership and produced 88 percent of the Republicans in Congress voting for his reprimand.” On Sunday, the Romney campaign put him up against former Pennsylvania congressman Bob Walker on CNN’s “State of the Union,” where Sununu hit Gingrich for his “$500,000 outstanding bill at Tiffany’s” and warned, “The conservatives that he has turned his back on should recognize the fact that he’s not a conservative.” And this week, Sununu has begun hitting the airwaves on conservative talk radio, telling host Scott Hennen that Gingrich is “not stable.”

All of this raises a question: Has the Romney campaign lost its mind?

No doubt Sununu’s support is important for Romney in New Hampshire, where he was a popular governor in the 1980s and served as chairman of the state Republican Party from 2009-2011. But Sununu is a discredited figure among conservatives. To deploy him on the national stage — in an effort to convince conservatives that Gingrich is not one of them — is, quite simply, insanity.

The New Hampshire newspaper the Union Leader reports that Sununu said in an interview last week, “Then-House Minority Whip Gingrich reneged after telling then-President George H.W. Bush (41) that he approved of the 1990 budget agreement with Democrats that included tax increases.” This is supposed to show that Gingrich is an unreliable leader. Gingrich denies ever supporting the deal, but even so: Gingrich ended up on the right side — opposing the Bush tax increase, which is still reviled by conservatives to this day. So the Romney campaign is attacking Gingrich for opposing a massive tax increase — and is doing so by using the White House chief of staff who brokered the deal in which Bush broke his “no new taxes” pledge.

How on earth does trotting out the mastermind of Bush’s still-hated “read my lips” tax flip-flop to attack Gingrich help Romney? This is not territory where Team Romney should want to tread. Conservatives’ biggest worry is that Romney will flip-flop the way “41” did on his tax pledge. Sending out a man responsible for that reversal as a national spokesman only helps Gingrich and raises questions about Romney’s judgment.

Sununu has also been attacking Gingrich for being reprimanded by Congress for ethics violations. Sununu is the wrong man for this job. Has the Romney campaign forgotten that Sununu was embroiled in an ethics scandal of his own?

As White House chief of staff, Sununu spent hundreds of thousands of taxpayer dollars flying on military jets to ski lodges, golf resorts, and even his dentist in Boston, as well as taking a government limousine to New York to attend a Christie’s stamp auction. He was investigated by the White House counsel’s office and forced to repay the government. A few months later, he was forced to resign. The New York Times reported “The uproar over the 1990 budget deal, in which Mr. Sununu was seen by many Republican lawmakers as a malevolent influence, exacerbated Mr. Sununu’s troubles. In the same fashion, he was badly wounded by disclosures of his extensive use of military aircraft for personal and political trips.”

Yet Team Romney decided Sununu was the right man to attack Gingrich for his troubled tenure as House speaker?

Conservatives have also not forgotten that Sununu was responsible for another of Bush’s most reviled decisions in office: his appointment of David Souter to the Supreme Court. In a 1990 interview with the New York Times, headlined “Sununu Tells How and Why He Pushed Souter for Court,” Sununu proudly took credit for Souter’s appointment — explaining what a great job he had done on New Hampshire’s Supreme Court and declaring: “I was looking for someone who would be a strict constructionist, consistent with basic conservative attitudes, and that’s what I got. . . . I was able to tell the President that I was sure he would do the same thing when he encountered Federal questions.” It didn’t exactly work out that way.

What possessed the Romney campaign to turn to John Sununu as their lead surrogate in going after Newt Gingrich? Hearing Sununu attack Gingrich is like nails on a chalkboard for the right — and can only push conservative voters further into the Gingrich camp. A word to the wise for the Romney campaign: Get John Sununu off the airwaves.