Harvard’s Institute of Politics buzzes with talk that its director, former New Hampshire Gov. Jeanne Shaheen (D), definitely wants a rematch with first-term Sen. John Sununu (R-N.H.) next year, but Granite State Democrats insist the deliberative Shaheen has not made up her mind yet.

The likelihood that Shaheen will quit her ivory tower for the campaign trail probably has increased with each new poll showing her beating Sununu handily in hypothetical matchups.

The latest survey, the University of New Hampshire’s Granite State poll, which is due out today, will be “consistent” with others giving Shaheen double-digit leads, according to Andrew Smith, director of the school’s Survey Center.

But good poll results do not automatically produce a candidate, nor do they win races. Shaheen ran strong in many polls leading up to the 2002 elections but wound up losing to Sununu by 4 points.

“I’ve heard so many different things,” Smith said about Shaheen’s Senatorial ambitions. “I think it’s really up in the air.”

Perhaps the latest rumors playing up the “inevitability” of a Shaheen candidacy is the product of politically green Harvard students’ enthusiastic prattle, but there is no question Shaheen is seriously testing the waters.

After appearing hesitant to make the race earlier in the year, Shaheen more recently has talked with Democratic Senatorial Campaign Committee officials, former staffers and even current Senators about a possible bid.

“She and I chatted very briefly and we’re going to talk but we have not yet sat down truly in-depth,” Sen. John Kerry of neighboring Massachusetts confirmed Wednesday. “We are going to and I know she’s thinking about [the race] and that’s where it’s at.”

Shaheen’s husband, Bill Shaheen, a political powerbroker in his own right, has said she will announce her decision “in the fall.”

Shaheen supporters, and even her would-be Democratic primary opponents, have all stressed that Shaheen can take all the time she needs.

Even so, there is no question that DSCC Chairman Charles Schumer (N.Y.) and current candidates Katrina Swett, Steve Marchand and Jay Buckey would like to know sooner rather than later.

Marchand, the mayor of Portsmouth who has pledged to step aside and back Shaheen should she enter the race, recently told The Manchester Union Leader that it is “very important” Shaheen make up her mind soon.

Swett, however, is not showing quite as much deference.

“At this point Katrina is moving forward with her campaign and that’s that,” according to Bob Quinn, Swett’s campaign manager.

Swett, whose husband is former Rep. Dick Swett (D-N.H.) and father is Rep. Tom Lantos (D-Calif.), already has banked more than $1 million for her campaign, and raised more than $700,000 from April 1 to June 30.

“Katrina and [Shaheen] have talked on several occasions,” Quinn said. “The Swetts have always been very supportive of the Shaheens, and the Shaheens have always been very supportive of the Swetts.”

The two women are good friends, but Swett has not said what she will do if Shaheen parachutes into the race.

Without declaring his candidate’s intentions, Quinn conceded that “Katrina would be very disappointed” if October or November arrived and then Shaheen made her move.

Practically speaking, Smith said: “I don’t think there’s any reason she has to decide very soon.”

Bill Shaheen is heading up the presidential effort of Sen. Hillary Rodham Clinton (D-N.Y.) in New Hampshire. That operation easily could be put to work for Shaheen, Smith said.

“The organization is there,” he said. “All she needs is the money, but she’ll be able to access the money. It doesn’t make sense for her to jump in now.”

Shaheen’s candidacy, which exists only as the “Draft Shaheen” effort begun by former New Hampshire Democratic Party Chairwoman Kathy Sullivan, is doing just fine without her.

In a Research 2000 poll, conducted July 9-11 for the Concord Monitor, Shaheen led Sununu 56 percent to 34 percent.

She was the only Democrat tested — in addition to the declared Democratic candidates, freshman Rep. Paul Hodes (N.H.) was included, too — who beat Sununu in a head-to-head matchup.

Hodes, who is not running for Senate, performed the next best, trailing Sununu 46 percent to 34 percent.

The survey of 600 likely voters had a 4-point margin of error.

Sununu earned the approval of 52 percent of those voters in regards to his job performance.

In a Suffolk University poll released at the end of June, Shaheen fared even better.

Her lead in the survey, which was conducted by American Research Group, was a whopping 28 points — 57 percent preferred Shaheen compared to 29 percent for Sununu.

In that poll, only 31 percent of voters said Sununu deserved re-election.

The DSCC seems tantalized.

“Gov. Shaheen is already ahead in three public polls and it’s clear that she would be a very formidable candidate,” DSCC spokesman Matt Miller said.