Inside Chris Christie's New Hampshire Resurgence

MANCHESTER, N.H. -- When Chris Christie was relegated to November's GOP "undercard debate," many assumed it would be the last they saw of the New Jersey governor. Four months into his presidential campaign, his national poll numbers had barely budged, languishing behind those of Donald Trump, Ben Carson and Sen. Ted Cruz.

In the past two weeks, though, Christie's fortunes seem to have changed. And they hinge on the state where he has invested nearly all his time: New Hampshire.

First, there was the new set of debate criteria from CNN, which will include polls from early-voting states like New Hampshire. Christie has spent 48 days there this year, second only to Sen. Lindsey Graham. He's averaging 6.3 percent in relevant statewide polls, which would easily carry him back to the main stage.

Then, on Sunday night, the stunner: a full endorsement from the New Hampshire Union Leader. The newspaper is the only one to reach all corners of the state, giving conservative publisher Joseph McQuaid one of the largest bully pulpits around.

"He is the one candidate who has the range and type of experience the nation desperately needs," McQuaid wrote. "Governor Christie is right for these dangerous times."

While many expected the paper to endorse a surging candidate like Sen. Marco Rubio, McQuaid dismissed the notion, declaring Americans "don't need another fast-talking, well-meaning freshman U.S. senator."

Rubio hasn't spent as much time in the state as Carly Fiorina, but the editorial rejected her, too: "We don't need as president some well-meaning private citizen who has no public experience," McQuaid wrote.

The pick could alter the trajectory of the Christie campaign, Dartmouth associate professor of government James Russell Muirhead Jr. said.

"The importance of the Union Leader endorsement for Christie can't be understated," he told ABC News. "The timing is good. It's going to take him time to ascend, if he's going to. If this came in January, it would have come too late."

The paper's endorsement isn't always predictive. Newt Gingrich won its support in 2012 before finishing fifth; John McCain won the state twice despite being picked only once.

It's not just the Union Leader that has Christie smiling, though. He has picked up several major endorsements from New Hampshire activists and elected officials in recent weeks. Renee Plummer, a well-known real estate developer who officially endorsed Christie today, said she had no idea that her pick would come on the heels of the Union Leader's.

"I love that he comes to these town halls and says, 'Ask me anything,'" she said, noting that he has held a whopping 35 such events. "And now with what's happened in the Union Leader, you're going to have people looking at him completely differently, saying, 'Hold on, let's look at him again.'"

Plummer will be joined by an even bigger pickup Tuesday: Donna Sytek, former speaker of the New Hampshire House of Representatives, according to a source close to the campaign.

Christie, 53, has also been staking out turf when it comes to New Hampshire's epidemic of heroin overdoses, which has claimed a record number of lives this year.

Rob Wieczorak, board chairman of the Farnum Center for Drug Recovery in Manchester, pledged his support to Christie earlier this month, after a video of the governor's town hall remarks on addiction went viral.

"He was the first candidate to focus on the drug problem," said Bill Greiner, a Bedford businessman and Christie supporter. "There are a lot of 'recovery voters' who appreciate that."

Greiner hosted his first Christie house party months ago. ("I jumped on the bandwagon before the wagon had wheels," he likes to say.)

But he thinks as endorsements - and visits - pile up, voters in New Hampshire will have Christie on the brain as they make their way to voting booths.

New Hampshire's primary, where Christie is betting it all, is scheduled for Feb. 9.

Professor Muirhead agrees that this could be Christie's moment, but cautions that he'll have to make up a lot of ground.

"He's really still in that second tier," he said. "Given where he's starting from, he's going to need all of the next eight weeks."