MANCHESTER, N.H.—Strolling through a factory that makes firefighter clothes, Jon Huntsman is about as animated as he gets—which is pretty subdued. He’s appropriately attentive to his hosts and politely shakes hands with workers. But what is palpably missing is electricity, a force of personality that’s made this GOP primary season a wild ride: Santorum’s fire, Paul’s quirkiness, Romney’s confidence, Gingrich’s arrogance, Bachmann’s misfires.

Indeed, one of the enduring mysteries of the 2012 presidential race is why Jon Huntsman’s candidacy turned out to be a dud. Was it the candidate or the ideological environment? Was it his message or his delivery?

The former Utah governor and ambassador to China seemed to be the man many feared last year—handsome with a stunning family, a shiny résumé with executive and foreign-policy credentials, and an ultraconservative record without the table-pounding ideology. Democrats were said to be so worried about facing off against him that President Obama appointed him ambassador to China to sideline him.

But all that was before Huntsman actually stepped into the ring. Almost from the day he announced his candidacy against the backdrop of the Statue of Liberty, the man could not get airborne. His name was misspelled on his announcement advisory. He angered the conservative base in his own party early on by seeming to dismiss them as extremists. And Democrats started to ignore him.

“The conventional wisdom is that he was unnecessarily confrontational toward conservatives early in his campaign, especially on issues like climate change … That confrontational approach, combined with his time in the Obama administration, allowed him to be unfairly typecast by a lot of GOP voters,” allows Dan Schnur, director of the Jesse M. Unruh Institute of Politics at USC.

And then there were the debates—a critical stage in this cycle for the candidates.

“They provided campaign-changing moments for Cain, Perry, Gingrich, and others. But Huntsman just sort of faded into the background and was never able to use them as a platform,” says Schnur.

Now Huntsman’s road to the White House comes down to the next few days in this bitterly cold state where he has done more than 150 events.

He has spent every waking minute here for months, skipping the Iowa caucuses—talking about creating more manufacturing jobs and ending U.S. involvement in Afghanistan. He hopes (and needs) to come in at least third in Tuesday’s primary. As the former Pennsylvania politician and Huntsman supporter Tom Ridge bluntly put it, Huntsman needs to “become part of the national debate.” And for a while he seemed to be doing better here, rising from the back of the pack to third or fourth place in polls. But Thursday’s latest Suffolk University/7News survey here has him slipping, with Santorum leap-frogging to third. Mitt Romney holds a strong lead with 41 percent, followed by Ron Paul (18 percent) and Rick Santorum (8 percent). Huntsman is tied with Newt Gingrich at 7 percent.“I came into the state as a margin-of-error candidate,” Huntsman said after the plant tour. “It is not 15 minutes of fame—it’s been a sustained, substantive rise.”The latest polling numbers reflect Santorum’s momentum coming out of Iowa, where only eight votes separated him from first-place winner Romney. Huntsman said this week that he has to exceed what he calls "market expectations" Tuesday—which Ridge defines as second or third place. He hopes to pull off the same kind of upset Santorum accomplished in Iowa. But that’s not at all a given for him at this point.Romney is considered a favorite son, having been governor of neighboring Massachusetts. Paul is also popular here, appealing to the state’s unaligned and independent voters—the same voters Huntsman wants. There are still 15 percent undecided.

He didn’t appear to close the deal with too many voters at the Global Manufacturing plant in Pittsfield—which is where his subdued personality might come into play.

Holly Michaud, who shook Huntsman’s hand, said she was “willing to look at him,” but she hasn’t made a decision yet. Ruth Lawrence was more direct. “He seems interesting, but I don’t know enough about him,” she said—a comment that does not bode well for Huntsman. Lawrence said she was torn between Romney and Paul.

Therein lies the problem with Huntsman: he remains everyone’s third choice.

But perhaps his biggest sin was to alienate the conservative base, not even pretending to be one of them, in a year when the far-right Tea Party has a grip on the GOP dynamic. Ironically, Huntsman’s positions and record are unflinchingly conservative: he’s pro-life, created a flat tax as governor of Utah, supports free trade, proposed a simplification of the federal tax code, and supported Rep. Paul Ryan’s budget plan to overhaul entitlements.

"He's plenty conservative, but his unwillingness to give the base red meat and his penchant for relying on logic and common sense doomed him from the start. Also, his rollout was horrible,” says Democratic operative Rodell Mollineau, president of American Bridge to the 21st Century.

GOP strategist Keith Appell puts it more bluntly:

"Clueless is as clueless does. 'Hey, everybody, I'm running to be your nominee, and my biggest qualification is that I worked in the Obama administration and even supported some of his failed and pathetic policies. Who's with me? And just for kicks and giggles, I think Obama's right about global warming, China is our friend, and I can tell really flat and dumb jokes.’”

For now, the experts say Huntsman's biggest challenge in New Hampshire is showing voters he can go the distance.

“Rarely does ideology trump electability here, and he hasn’t made himself central to the equation,” says Patrick Griffin, senior fellow at the Institute of Politics at Saint Anselm College. “Voters want a winner, and they don’t see a winner.”