Newt Gingrich is facing an identity crisis that could undo his campaign: stay positive, or go negative.

Everyone expected a deluge of attacks to descend on the former Speaker, and Gingrich was bent on ignoring them and maintaining the positive focus that, along with the debates, had helped him rise to the top. He even instructed his staff to keep a positive tone, and one Iowa staffer had to resign after calling Mormonism — rival Mitt Romney’s religion — a cult.

In a way, running a positive campaign was almost a necessity for Gingrich. He’s so very vulnerable to attacks — from his support for an individual healthcare mandate to his consulting work to his personal infidelities — that his best shot at winning was always in an environment free from acrimony and negativity.

But by promising to stay positive, he gives up the opportunity to fight back, and thus, when he does, it’s immediately called hypocritical. In short, Gingrich is fighting with a hand tied behind his back — one he’s bound himself.

He discovered that when he tried firing back.

At first, Gingrich appeared to be staying on message and not taking the bait from his rivals. For a week after ordering his campaign to stay positive, he endured a series of stinging attacks from his opponents, without hitting back.

Ron Paul released an ad accusing Gingrich of “serial hypocrisy.” Michele BachmannMichele Marie BachmannBachmann won't run for Franken's Senate seat because she did not hear a 'call from God' Billboard from ‘God’ tells Michele Bachmann not to run for Senate Pawlenty opts out of Senate run in Minnesota MORE implied he was corrupt by claiming on Fox News that he was “on the take” with Freddie Mac — a reference to his consulting work on behalf of the mortgage giant. And Rick Perry hit the airwaves with an ad highlighting Gingrich’s former support for the individual heathcare mandate.

Then the Romney guns started firing, and did so bruisingly.

First, during a conference call with the press, two Romney surrogates — former Missouri Sen. Jim Talent and former New Hampshire Gov. John Sununu — accused Gingrich of being “outrageous” and “irrational." Both of those descriptions went beyond normal political attacks by implying Gingrich wasn’t temperamentally qualified to be president.

And Romney, trailing Gingrich in the polls at that time, joined the fray, telling The New York Times: “Zany is not what we need in a president.”

That’s not just violating Ronald Reagan’s 11th Commandment. That’s annihilating it. Imagine the Democratic National Committee trotting out Romney and his surrogates’ comments if Gingrich won the nomination: “Zany,” “outrageous” and “irrational.” Those are charges that Gingrich doesn’t meet the threshold of being presidential, and all severely hurt the Republican cause.

After an additional barrage of attacks, Gingrich finally fought back, but did so with a wild swing after Romney attacked him for the money he earned from his consulting work with Freddie Mac.

Gingrich told reporters at a gaggle in New Hampshire: “I would just say that if Gov. Romney would like to give back all the money he’s earned from bankrupting companies and laying off employees over his years at Bain, that I’ll be glad to then listen to him.”

The negative reaction was instantaneous. Commentator George Will spoke for many conservatives when he wrote in an op-ed that the remarks were a “capital crime” and wondered where Gingrich’s promise to remain positive had gone.

“This departure from his pledge that his campaign ‘will be relentlessly positive’ represents the virtue of recycling applied to politics,” Will wrote.

After being asked about it by Fox News’s Sean Hannity, Gingrich retracted his remarks.

“There was a very brief moment where, frankly, he [Romney] got under my skin, and I responded in a way that made no sense [and] doesn’t fit my values.” He added that Romney was a “good businessman” and a “good manager.”

It was a full retraction, highlighted by praise for Romney.

Romney, on the other hand, never apologized for calling Gingrich “zany,” nor did his surrogates, and he remained on the offensive, while Gingrich’s apology became the big story.

All of it was a problem of Gingrich’s own making, and once again, Gingrich had vacillated between the promise to stay positive and a nasty counterpunch that went too far.

In order to stanch the bleeding, Gingrich might have to openly discard the promise of positivity and make someone else bleed, too.