Republicans have flirted with so many potential challengers to Mitt Romney for the party's presidential nomination that it is tempting to dismiss Newt Gingrich as just the latest transient beneficiary of the rank-and-file's restlessness.
But the 68-year-old ex-Speaker of the House of the Representatives has one thing going for him that none of the other anybody-but-Romney pretenders have enjoyed: nostalgia.
Mr. Gingrich's colossal clashes with Bill Clinton live on fondly in the memories of grassroots Republicans, who like their politics raw and remorseless. And few can think of another candidate who would as belligerently bait President Barack Obama on the campaign trail.
Mr. Gingrich had many Republicans salivating when the acid-tongued tormentor of Democrats evoked the prospect of debating Mr. Obama next fall.
"Obama has $1-billion to spend trying to smear his opponent and the only way you can break through is the debates," Mr. Gingrich offered on a campaign stop in New Hampshire this week. "Who would you like to have on the same platform?"
A plurality of Republicans is suddenly answering "Newt" and resuscitating a campaign that had been written off as dead almost as soon as it was born. In three separate polls this week, the former college history professor surged past Mr. Romney to become the GOP front-runner.
During his 1990s heyday, Mr. Gingrich forced a government shutdown over the budget and led the impeachment proceedings against Mr. Clinton over the Monica Lewinsky scandal. That legacy may explain why the ex-Speaker draws disproportionate support among Republicans over 65, who punch above their weight in GOP primaries.
Of course, the very "qualities" that have Republicans taking a second look at Mr. Gingrich now make him insufferable in the eyes of many unaligned American voters. He is usually windy, invariably self-congratulatory and always polarizing. To wit, his latest political tome is titled Saving America: Stopping Obama's Socialist Secular Machine.
But Mr. Gingrich's reputation as an uncompromising hard-heart – he made the cover of Newsweek as the Grinch in 1994 – took it in the shins during Tuesday's GOP debate when he advocated granting legal status to millions of illegal immigrants with families. It made him seem like the compassionate alternative among his hard-line rivals.
That is not to say it was a smart move. While it could endear him to Hispanic voters, a primary debate is an inhospitable venue to challenge the anti-amnesty orthodoxy of the modern GOP. Texas Governor Rick Perry already proved that.
"Immigration is one of the most emotional and divisive issues in Republican primary politics. You usually don't try to be a statesman when you're trying to win the nomination," said Merle Black, a political science professor at Emory University in Atlanta. "But Newt's not a conventional politician. He's sui generis."
The coming days will tell whether Republican voters are willing to give him a pass on the immigration issue. A similar outburst by Mr. Perry, who signed legislation allowing illegal immigrants to pay in-state tuition fees in Texas, was the beginning of the end of his honeymoon with national conservatives.
"I can't imagine any serious person in this country that says we are going to tear families apart who have been here 20 or 30 years," Mr. Gingrich told CNN after the debate, echoing Mr. Perry's suggestion that opponents of in-state tuition "did not have a heart."
Republicans who oppose any whiff of amnesty – which is to say, the vast majority of them – are not likely to take kindly to Mr. Gingrich's depiction of them as unserious.
But that is only one reason why his stint near the top of the polls may be as fleeting as those of Mr. Perry, Herman Cain and Michele Bachmann. As the saying goes, Mr. Gingrich has more baggage than Delta Airlines.
Thrice-married, he was having an affair while railing against Mr. Clinton's indiscretions; he has racked up millions in consulting fees since leaving office by plying his Republican connections for the likes of now-bankrupt mortgage insurer Freddie Mac; he once appeared with Democratic lioness Nancy Pelosi in an ad decrying climate change; he was for requiring all Americans to buy health insurance (the linchpin of Mr. Obama's reform legislation) before he was against it; he and wife Callista (she of the $500,000 Tiffany's credit line) are known to appreciate the finer things in life.
Any one of those factors could be fatal in the GOP primary, especially for a candidate courting social conservatives in the crucial early voting states of Iowa and South Carolina. But if anything does Mr. Gingrich in, it will likely be his own indiscipline.
"He's never on message," Prof. Black quipped. "If you let him talk long enough he'll throw out three or four things that will blow his campaign apart. That's his history."
And the historian who should know better has a habit of repeating it.