Mayor Martin J. Walsh will formally endorse Democratic front-runner Hillary Clinton today, a move analysts say will further solidify her status as the left’s most electable presidential hopeful.

“She’s the best-qualified candidate in my opinion that’s running for office right now, with the challenges that our country faces,” Walsh told the Herald yesterday.

“I think what’s happening on the other side, I don’t see an answer there for continuing to move our country forward.”

The announcement comes after several weeks of speculation about the mayor’s potential endorsement.

He declined to comment on the issue in early October after he praised Clinton for her commitment to combating the heroin epidemic.

“No comment on that right now,” Walsh said when asked about an endorsement following a drug abuse forum with Clinton and Attorney General Maura Healey in Dorchester.

But Walsh has decided to formally extend his support, which will be announced at the “Hard Hats for Hillary” political rally at Faneuil Hall this afternoon.

Walsh is scheduled to discuss Clinton’s involvement in labor issues. More than a dozen national labor unions have endorsed Clinton’s candidacy.

Walsh said Clinton’s time serving as a New York senator, secretary of state and her stint in the White House as first lady all factored into his decision to support her.

“She has the most well-rounded resume,” he said.

Dave Hopkins, political science professor at Boston College, said Walsh’s endorsement is a sign that officials in the Democratic Party view her as the most realistic choice.

“It suggests she’s seen as a safe course to bet on in terms of getting the nomination,” Hopkins said.

“The elected officials and organization leaders within the party are interested in electability, as well as ideology.”

Dennis Hale, also a Boston College political science professor, said Clinton’s high-profile hobnobbing and upper middle-class background runs counter to Walsh’s average Joe appeal.

But Hale said Walsh, previously a labor leader, is left with few options.

“He can’t endorse Bernie Sanders because he’s not a serious candidate, and Martin O’Malley isn’t going anywhere,” Hale said.

“She’s not his kind of Democrat,” but, Hale said, as long as he’s sticking with the Democrats, Walsh “has no choice.”

Doors open for the rally at 1:30 p.m. and the program is scheduled to begin at 2:30 p.m.