MANCHESTER, N.H. — Several of New Hampshire’s top Democratic figures are holding back their endorsements in the state’s first-in-the-nation primary, which party insiders view as another sign of mounting troubles for Hillary Rodham Clinton’s campaign.
Most of the state’s Democratic Party establishment lined up behind Mrs. Clinton early in the race. But prominent leaders, including New Hampshire Gov. Maggie Hassan, have kept quiet as the nomination race has grown increasingly tight between Mrs. Clinton and Sen. Bernard Sanders, a Vermont independent who is running as a Democrat.
“There are those who are waiting because they don’t want to be caught backing the wrong horse,” said John White, the Democratic Party chairman for Wolfeboro, New Hampshire. “There are people who now seriously doubt that Hillary is going to take the New Hampshire primary, and they want to be in good shape with the winner.”
In 2008, when Ms. Hassan was the majority leader of the state Senate, her support helped boost Mrs. Clinton to a comeback win in the New Hampshire primary that keep the former first lady in the race against Barack Obama.
As governor this election cycle, Ms. Hassan could hold an even more crucial endorsement for Mrs. Clinton.
Sources close to Ms. Hassan said she was too busy dealing with the state’s budget to worry about endorsements. She has been locked in a stalemate with Republican lawmakers for months after vetoing the budget.
Rep. Ann M. Kuster, who backed Mr. Obama in 2008, is another top New Hampshire Democrat withholding an endorsement. Her office did not respond to questions about an endorsement.
Other top Democrats have said they support Mrs. Clinton but stop short of formally announcing endorsements.
Sen. Jeanne Shaheen threw her support behind Mrs. Clinton before the race started by signing a 2013 letter with every fellow Senate Democratic woman urging the former first lady, senator and secretary of state to get into the White House race.
Yet Ms. Shaheen hasn’t announced her endorsement.
As evidence of the Ms. Shaheen’s public support, spokesman Ryan Nickel pointed to the 2013 letter and an email Ms. Shaheen sent after Mrs. Clinton announced her candidacy in April.
However, he did not respond to an inquiry from The Washington Times about whether Ms. Shaheen would make a formal endorsement.
Lou D’Allesandro, a nine-term state senator and icon of New Hampshire politics, also said his support for Mrs. Clinton is widely known, though he too has not made a formal endorsement.
The Clinton campaign could be strategically delaying endorsements from big guns such as Ms. Hassan, Ms. Shaheen and Mr. D’Allesandro for their announcements to get the most impact at key moments in the race.
Still, even Mrs. Clinton’s supporters are unsure whether they have picked a winner as Mr. Sanders gains momentum and Mrs. Clinton continues to be dogged by a State Department email scandal.
Mr. D’Allesandro acknowledged what he called “a great deal of turbulence” in the race, including waves made by Republican candidate Donald Trump and the groundswell of support for Mr. Sanders.
“Bernie Sanders is out working up the crowds. I think it’s a different environment, it’s a different political world as we speak, and we have to work our way through it. She’s going to work her way through it,” Mr. D’Allesandro said.
“When the going gets tough, the tough get going,” he said. “She’s a tough lady. She’s very committed, very dedicated, very bright, very capable. You know, this politics is a tough business, a very, very tough business. I’ve been around it a long time, and it’s not getting any easier.”
Mr. Sanders, the die-hard socialist who has emerged as Mrs. Clinton’s chief Democratic rival in New Hampshire and across the country, has been drawing the largest crowds of any presidential candidate this year and has steadily gained on Mrs. Clinton in the polls.
He surged past Mrs. Clinton 44 percent to 37 percent in a recent Boston Herald/Franklin Pierce University poll of likely Democratic primary voters in the Granite State.
Mr. White, the party chairman in Wolfeboro, said he would remain neutral in the race in an effort to retain party unity. He said he wanted to avoid the split in the party that occurred in 2008.
“In 2008, there was a big division of Hillary people and Obama people. And after the nomination was settled, a large number of the Hillary people went off in a snit and didn’t even vote, and they are still pissed off, some of them,” he said. “I’m working like hell to keep that kind of a split from happening this time.”