MANCHESTER, N.H. – What a difference a year makes.

An overflow crowd attends a town hall with former senator Rick Santorum in Hollis, N.H. (Justin Sullivan/Getty Images)

Two months later, the New Hampshire Republican State Committee elected as its party chairman Jack Kimball, a tea party-backed businessman with no political experience who bested establishment candidate Juliana Bergeron in an upset win.

Now, on the eve of this election year’s first-in-the-nation presidential primary, the tea party’s influence on the GOP is unmistakably on the wane. Kimball is out after a rocky seven months at the helm; Guinta likely faces a tough reelection bid; and – most ominous-- for the first time more than 50 percent of likely GOP voters in New Hampshire say that they do not support the smaller-government, anti-tax movement.

What happened?

As is often the case in politics, the answer is a mix of national and local.

Nationally, the public’s views of the tea party have been cooling for the better part of a year. A November Pew Research Center survey showed that during the 2010 midterms, 27 percent of Americans said they agreed with the tea party, while 22 percent disagreed. A year later, those numbers were nearly reversed: 27 percent said they disagreed with the movement, while 20 percent said they agreed. More than half of respondents said they had no opinion.

Those numbers are reflected in the most recent polls of likely New Hampshire GOP primary voters.

An NBC News/Marist poll released late Friday showed that for the first time, 53 percent of likely Republican primary voters said they are not supporters of the tea party, while 40 percent said they are supporters and seven percent were unsure.

That was an uptick in opposition to the movement from October, when 47 percent of likely voters said they did not support the tea party, 42 percent said they did support it and nine percent were undecided.

The latest Suffolk University/7 News tracking poll shows an even more drastic shift.

In mid-September, 48 percent of likely Republican primary voters polled by Suffolk University described themselves as supporters of the tea party, while 40 percent said they were not, and 12 percent were undecided.

Now, in the latest tracking poll, support for the movement has plummeted 11 points – from 48 percent to 37 percent of likely GOP primary voters. Opposition has risen four points, from 40 percent to 44 percent. Nineteen percent are undecided.

While the drop in support for the tea party in New Hampshire dovetails with national trends, not all early states are seeing a similar decline. In fact, in two states with a conservative-leaning GOP electorate – Iowa and South Carolina – support has held steady or been rising in recent months.

In Iowa, which held its caucuses last week, 64 percent of those who voted were tea-party supporters, according to exit polls. Twenty-four percent described themselves as neutral, and 10 percent said they opposed the tea party.

That’s on par with the 65 percent of likely Iowa GOP caucus-goers in a July Mason-Dixon poll who said the phrase “tea party supporter” described them “very well” or “somewhat well.”

And in South Carolina, an early December NBC News/Marist poll shows support for the tea party stands at 51 percent among likely GOP primary voters, while 40 percent say they do not back the movement, and nine percent are unsure.

That’s actually an increase in support from October, when 45 percent of likely GOP voters in South Carolina said they backed the tea party, 44 percent said they did not, and 10 percent were unsure.

There’s another possible explanation for why the tea party has been losing favor in New Hampshire: the state’s local politics, particularly when it comes to the New Hampshire Republican Party chairmanship.

In January 2010, Kimball l eked out a narrow 222-to-199 win among members of the state Republican Committee in the chairmanship race. But his tenure at the party helm was quickly beset by allegations of corruption and incompetence.

As pressure mounted from within his own party to resign – including from Ayotte, Guinta and others who rode the 2010 tea party wave -- Kimball defiantly declared that he would not step down. He then reversed course a few days later, and Wayne MacDonald, then the party’s vice chairman, stepped into the chairmanship.

The episode may have served as a cautionary tale of the challenges that come with elevating a tea party-backed newcomer to political office. MacDonald, has a resume that contrasts sharply with Kimball’s: His biography on the New Hampshire Republican Party Web site notes that he has “political experience spanning more than three decades” and has served “at every level” in the state committee.

What does it all mean for Tuesday’s primary?

It’s the latest explanation for why former Massachusetts governor Mitt Romney (R) is going from strength to strength in the Granite State.

The Iowa exit polls show that tea party supporters were fractured in last week’s caucuses: 29 percent backed former senator Rick Santorum, while 19 percent backed Rep. Ron Paul (Texas); 19 percent backed Romney; 15 percent supported former House speaker Newt Gingrich (Ga.); and 11 percent voted for former Texas Gov. Rick Perry.

Tea party opponents, however, were far more unified: 43 percent of them voted for Romney. A plurality of those who said they were neutral about the tea party also voted for Romney -- he took 32 percent.

So, the fewer likely GOP primary voters in New Hampshire who say the support the tea party, the better the odds are for Romney.

In a sign that tea party supporters in the Granite State are also unlikely to rally behind a single candidate on primary day, Guinta has said that he is declining to endorse a particular candidate.

And, notably, Paul – who has been hailed as a congressman who was “tea party before there was a tea party” – has been buoyed more by young voters (he won 48 percent of 17- to-29-year-olds in Iowa) than by tea party backers. Some of his most ardent fans in the Granite State were chagrined about the slack in tea party support over the weekend.

“Ron Paul is the founding father of the tea party. Don’t call yourself a tea party and then spit on the guy that started it,” Glen Aldrich, a 54-year-old unemployed carpenter from Guilford, said as he stood outside of Paul’s Sunday event in Meredith rounding up support for the candidate.

Aldrich noted that last month, the Lakes Region Tea Party, which meets just down the street from where Paul’s event was held, backed Gingrich in an informal straw poll of its members. Seventeen members backed Gingrich; 12 members cast ballots for Romney; only three voted for Paul.

“Wow,” Aldrich said of his reaction to the poll results. “I said, ‘No reason for me to go there. Ain’t too many people think like I do.’ I considered myself a tea-partier until then.”

Today on the trail (Courtesy of the PBS NewsHour Political Calendar and campaign advisories; all times Eastern):

8 a.m.: Newt Gingrich holds a breakfast meet-and-greet at the Philbricks’ Residence in Dover, N.H.

8 a.m.: Jon Huntsman visits Fort Harry’s Restaurant in Lebanon, N.H.

8:30 a.m.: Rick Perry holds a meet-and-greet at Mama Penn’s in Anderson, S.C.

8:45 a.m.: Ron Paul has breakfast at Moe Joe’s diner in Manchester, N.H.

8:45 a.m.: Jon Huntsman visits Daddy Pop’s Tumble Inn Diner in Claremont, N.H.

10:15 a.m.: Rick Perry holds a campaign event at the Pickens County Courthouse in Pickens, S.C.

10:15 a.m.: Jon Huntsman Mary’s Bakery and Cafe in Henniker, N.H.

10:30 a.m.: Ron Paul holds a meet-and-greet in Hollis, N.H.

11 a.m.: Newt Gingrich holds a town hall at PSNH in Manchester, N.H.

11:15 a.m.: Jon Huntsman visits Eagle Square in Concord, N.H.

11:30 a.m.: Mitt Romney holds a town hall at the Gilchrist Metal Fabricating Company in Hudson, N.H.

12:05 p.m.: Rick Perry campaigns at the Poinsett Club in Greenville, S.C.

1 p.m.: Newt Gingrich holds a meet-and-greet at the Nashua Country Club in Nashua, N.H.

1 p.m.: Jon Huntsman visits Harvey’s Bakery in Dover, N.H.

2 p.m.: Newt Gingrich holds a town hall at BAE Systems in Nashua, N.H.

3 p.m.: Ron Paul holds a rally in Concord, N.H.

3:45 p.m.: Jon Huntsman visits Crosby’s Bakery in Nashua, N.H.

4 p.m.: Newt Gingrich holds a town hall at the American Legion Hall in Hudson, N.H.

5:30 p.m.: Rick Perry holds a meet-and-greet at Stax’s Original Restaurant in Greenville, S.C.

6 p.m.: Newt Gingrich holds a campaign event at his campaign headquarters in Manchester, N.H.

6 p.m.: Mitt Romney holds a rally in Bedford, N.H.

7 p.m.: Jon Huntsman holds a rally at Exeter Town Hall in Exeter, N.H.

9 p.m.: Newt Gingrich holds a BCS Football Party at The Draft in Concord, N.H.