One of the first signs that City Councilor Tito Jackson was in political purgatory came on a cold afternoon in January, as he stood outside a Dudley Square cafe and announced he was running for mayor.
None of his council colleagues showed up.
Nor did they attend his annual turkey fry in May, which typically attracts high-ranking Democrats, including Suffolk County Sheriff Steven W. Tompkins, who was a no-show this year. These days Tompkins, like a majority of Jackson’s colleagues and members of Boston’s political establishment, is supporting Mayor Martin J. Walsh.
With less than six weeks until Election Day, the icy political treatment has become Jackson’s reality. He trailed Walsh by more than 30 percentage points in the Sept. 26 preliminary election and is now contending with the political isolation that comes with attempting to oust a popular mayor.
Ten of his 12 council colleagues have publicly endorsed the mayor. One councilor — Ayanna Pressley, whose husband is employed by the mayor — has said she is neutral. Councilor Andrea Campbell has ignored repeated requests for comment about whom she is backing.
Unions, ward committees, and Democratic Party faithfuls are lining up for Walsh. And even some of Jackson’s close allies, who would only speak privately for this story, refused to publicly say one good thing about him.
Jackson said he is not discouraged by the cold shoulder. He said the residents he has met while door-knocking throughout the city won’t allow him to give up on the issues they value.
“The political establishment is going to do what the political establishment does — it is going to support itself,’’ Jackson said. “It is going to support the status quo and attempt to assure victory for the same old. I am absolutely not the same old.”
To be sure, Jackson’s mayoral race was always going to be a formidable challenge. In Boston politics, incumbents seldom lose, and challengers must fend for themselves with little money, a scrappy organization, and few supporters. People with business in front of the city know who to get behind.
“The political community, the business community, they don’t want anything to do with you,” said a former city councilor, Michael McCormack, who follows Boston politics closely. “They don’t want to be seen as an ally of someone who is opposing the mayor.”
Thomas M. Menino and Ray Flynn — mayors of years past — simply ignored their challengers, McCormack said, and got their followers to do the same.
Councilor Michael Flaherty knows that banished feeling all too well: he recalled the political isolation he endured after he tried to unseat Menino in 2009.
He said administration officials leaped out of photo shoots — and elevators — for fear of being seen with or talking to him before Election Day. Flaherty said Menino and his supporters avoided him at ribbon-cuttings and groundbreakings. His childhood friends remained loyal, but some paid a price for siding with the mayor’s opponent, the councilor said.
“People’s jobs and livelihood were threatened,’’ Flaherty said. “That’s how it worked under the Menino regime.”
In Flaherty’s view, things are different now: Walsh has been more gracious to his opponents than Menino was, and he does not makes politics personal. Throughout the campaign, Walsh and Jackson have appeared at public events, posing for pictures together, shaking hands, and at times embracing.
Jackson said he has been in discussions with many elected officials and community leaders about supporting his candidacy. Not everyone has offered support, he said. But he’s encouraged by the coalition he is building.
Darnell Williams, president of the Urban League of Eastern Massachusetts, who has not said whom he is supporting, described the political climate as “Et tu, Brute” — an unexpected betrayal.
“People will tell you what they want you to hear — until you get into that political water,’’ he said. “Once you are in, you [realize] it is full of sharks.”
Four years ago, Jackson himself was part of the political establishment that lined up with Walsh, leaving challenger John Connolly, a former city councilor, in the dark.
Now, the Massachusetts Black and Latino Legislative Caucus, a support system for lawmakers of color, has also gone quiet about him.
State Representative Russell Holmes, the former head of the caucus, would not declare who he will back in the mayoral race but said Jackson is aware of the force blowing against him.
“I think it takes an enormous amount of courage to go against the most influential incumbency . . . in the state,’’ Holmes said of Jackson. “And I admire his courage.”
State Senator Linda Dorcena Forry — a neighbor and former legislative colleague of Walsh — said she has worked with Jackson and noted that he is raising issues that are important to her, such as income inequality and affordable housing.
“It’s not icing out [Jackson],” she said. “Folks recognize that there are relationships in this business, and that’s real. I don’t think folks should walk away from that.”
Jackson’s supporters said the councilor has asked people who have previously backed him to endorse his campaign. Mostly, they said, they have turned him down, telling him it wasn’t his time to run — a response Jackson’s supporters view as an insult.
“It’s not insulting to me,’’ Jackson said. “The question is whether it is insulting to democracy, whether it is insulting to fairness, and whether it is insulting to people of the city of Boston.”
Tompkins, the sheriff, said he is backing the mayor because the two have been doing work to end criminal recidivism and he wants those efforts to continue. The sheriff had teamed up with Jackson in 2015 to host a council hearing at the county jail on ending recidivism.
He said Jackson called him in January and again in the summer to ask for his support. But he told Jackson he’s with Walsh, who has since opened an office that helps former inmates returning to society.
“I’m vested in him,’’ he said. “That is not something that I am going to put in jeopardy.”
Tompkins also spoke about Jackson’s turkey fry, saying he did not attend this year because he had taken time out of the political circuit to heal after his wife died last year.
He said he “might have” attended before, “one or two” times. But people close to the event said that last year the Sheriff’s Department had a table at the event, which was held at Jackson’s home.Meghan E. Irons can be reached at email@example.com. Follow her on Twitter @meghanirons.