GOFFSTOWN, N.H. — Jeanne Shaheen stood in a college auditorium Tuesday, her political pedigree staring down from the walls around her: An oversized snapshot of Shaheen and her husband with Jimmy Carter; Shaheen sitting next to presidential hopeful Gary Hart.
The photographs offered black and white evidence of her enduring place atop the Granite State’s politics, proof of a life, from operative to governor to US senator, spent in power.
But now that position is threatened from the outside. National winds are blowing against Democrats, and Shaheen faces a potential challenge from former Massachusetts senator Scott Brown, who has already pulled off one now-legendary upset.
Brown, who announced an exploratory committee last Friday, has pounced on Shaheen’s vote in favor of the Affordable Care Act, tried to frame her as an “Obama Democrat,” and said she is disconnected from the concerns of her constituents.
Shaheen and her Democratic allies believe that her decades-long foundation in New Hampshire will help insulate her from Republican attacks and the potentially nasty political climate forecasters say the Democrats are likely to face in November.
“I’ve been frenetically going around New Hampshire for the last 5½ years, working on the issues that matter to the people of this state, and I don’t intend to change that,” Shaheen told reporters after talking with the students at the New Hampshire Institute of Politics at St. Anselm College.
But that hard work and Shaheen’s stature may not be enough if Brown, a seasoned candidate familiar with the spotlight of two nationally watched campaigns, makes his bid official, as both Democrats and Republicans expect him to do.
His foray has already heartened members of the GOP, eager to wrest control of the Senate from Democrats. Republicans reason that a Brown candidacy would, at least, force Democrats to spend heavily there, drawing resources from other races.
Brown’s strategy, people close to him say, centers on trying to depict Shaheen as disconnected from workaday New Hampshire residents and shackling her not only to the most unpopular elements of Obama’s record, including the health care law, but to the president himself.
After Obama praised Shaheen in a televised NECN interview Wednesday, Brown hit back.
“President Obama and Jeanne Shaheen are joined at the hip,” Brown said in a statement Thursday. “If it wasn’t for Jeanne Shaheen, Obamacare would not have become the law of the land.”
The troubled implementation of the Affordable Care Act is just one part of a darkening electoral picture for Democrats.
“The national environment is not helpful at this time,” said former US senator Bob Graham, a Florida Democrat. “The president’s approval levels, the consternation about Obamacare, all of the uncertainties around the world are challenges.”
Nonetheless, Shaheen would still enter the general election with several advantages, if Brown wins the GOP primary against a field that includes former US senator Bob Smith, former state senator Jim Rubens, and conservative activist Karen Testerman.
Shaheen is a popular member of one of the state’s most prominent political families, her husband a decades-long powerbroker in state politics. She has won statewide campaigns four times, with just one loss: the 2002 US Senate race won by Republican John E. Sununu.
A Suffolk University poll released earlier this month showed that Brown, who lost in Massachusetts two years ago despite strong favorability ratings, would enter the race with more Granite Staters viewing him negatively than positively. That poll gave Shaheen a lead of 52 percent to 39 percent in a hypothetical matchup.
Democrats have already begun to paint Brown as a political opportunist, an office-shopper eager to trade on the celebrity he earned in 2010 by winning the Massachusetts seat opened by Senator Edward M. Kennedy’s death, and as someone more concerned with his career than with serving constituents.
“You’ve got Jeanne Shaheen, who has fought long and hard for the people of New Hampshire, and you’ve got Scott Brown, who has flirted with every office imaginable,” said Ty Matsdorf, an adviser to Senate Majority PAC, a political action committee that supports Democratic candidates.
In turn, Brown has tried to jiu-jitsu that line of attack. On Tuesday, he called the carpetbagger label derogatory and insulting to many New Hampshire residents who have moved from other states.
Both Shaheen and Brown may soon be buffeted by factors beyond their control. Brown’s refusal to sign a pact limiting outside spending virtually ensures that the state will be deluged by millions of dollars in advertising paid for by groups not directly affiliated with either campaign.
A number of national Democratic strategists acknowledge that a Shaheen-Brown race would be competitive and that Shaheen could be dragged down by the president’s low approval ratings.
But these strategists argued that her long tenure in the state — as a former state lawmaker and, in particular, as governor for six years — will help insulate her from a national environment that currently favors Republicans. They were bullish she will be victorious come November.
“In a state like New Hampshire, where someone like Jeanne Shaheen has been so deeply involved for so long, the environment doesn’t affect her as much,” said Democratic pollster Mark Mellman. “People know her well, know what she’s been doing.”
Brown strategists, though, note that the voter enrollment numbers that doomed him in Massachusetts against Elizabeth Warren in 2012 are more favorable for him north of the border.
In New Hampshire, Republicans hold a 3-point edge over Democrats in registered voters. In Massachusetts in 2012, registered Democrats outnumbered Republicans by more than 3 to 1. Unenrolled voters account for the largest bloc in both states.
The New Hampshire enrollment figures mean that Brown could lose independents, draw no Democratic support, and still win. That’s a stark difference from Massachusetts two years ago, when he needed to win unenrolled voters and pick off a chunk of Democrats.
Both Shaheen’s effort to curb outside spending, and Brown’s resistance, are strategic. Nationally, outside groups supporting Republicans are expected to outspend Democrats heavily in this election cycle. That represents a political dislocation, as state borders blur and national influences in statewide races grow.
The chance the race will be shaped by broader forces is increased by the election’s spot on the calendar. New Hampshire, as it does every four years by dint of its status hosting the first presidential primary, will again become a focus of presidential campaign interest, with candidates from both parties ramping up visits to the state.
Perhaps more than in past years, White House hopefuls will find a state already being shaped by the political zeitgeist beyond its borders.
“There are very few places that buck national trends anymore,” said Republican pollster Whit Ayres. “Almost all politics is national now. New Hampshire will not escape the national mood.”Jim O’Sullivan can be reached at Jim.OSullivan@globe.com. Follow him on Twitter at @JOSreports. Joshua Miller can be reached at Joshua.Miller@globe.com. Follow him on Twitter at @jm_bos.