Dianne Wilkerson, the state's lone black senator and one of Beacon Hill's most controversial figures, lost in yesterday's primary by a paper-thin margin to a second-time challenger in a race in which Wilkerson's legal issues apparently overshadowed her high-profile endorsements and her record.
Sonia Chang-Díaz, a 30-year-old former Jamaica Plain schoolteacher and the daughter of an astronaut, defeated the 15-year incumbent who had the backing of top state Democrats including Governor Deval Patrick but was weakened by campaign finance and past legal troubles that left many voters in the vast and diverse Boston district demanding fresh representation.
Chang-Díaz garnered 50.57 percent of the vote to 49.29 percent for Wilkerson, or 9,051 to 8,823 votes, a 228-vote margin. Reflecting light voter turnout statewide, just 14 percent of Boston's electorate went to the polls.
Pending the results of a possible recount, which Wilkerson would have to request, Chang-Díaz will face a little-known Socialist Workers Party candidate, William Theodore Leonard, in the Nov. 4 general election. There is no Republican candidate.
"I stand here before you, honored to the core to be your Democratic nominee for the state Senate," a jubilant Chang-Díaz said, standing on a chair in front of more than 100 supporters and volunteers at the Alchemist Restaurant and Lounge in Jamaica Plain. Chang-Díaz said she received a concession call from Wilkerson at about 11:15 last night.
Wilkerson supporters packed into Roxbury's Hen House Wings 'n Waffles last night and showered the defeated state senator with a five-minute ovation before she stepped onto a crate to tell them she would "be OK."
"I'm going to finish what I started to the extent that I can do that this year," Wilkerson said. "It's been a long day, and I'm not going to let you all leave here feeling defeated."
Wilkerson later told reporters she had not decided whether to seek a recount, but she offered a qualified concession.
"As far as I know tonight, she is the winner," said Wilkerson, dressed in a vibrant red dress, matching the red and white balloons and signs surrounding her.
The hard-fought primary, in which both candidates raised more than $100,000, was a rematch of the 2006 primary election in which Wilkerson edged Chang-Díaz by 6 percent. In this contest, Wilkerson urged constituents to remember her long record of service on issues such as gay rights, racial profiling, and predatory lending.
She commanded strong support from top politicians including Patrick and Mayor Thomas M. Menino, who both recorded messages of support sent to voters in automated calls and played on radio stations.
But Chang-Díaz spent much of her campaign pounding Wilkerson on ethics issues, and those transgressions clearly were on voters' minds.
In August, Wilkerson paid a $10,000 fine to the state attorney general's office and acknowledged campaign finance violations dating back to 2000 and related to improper reimbursements of campaign contributions to herself and failing to report some contributions.
She also once faced foreclosure proceedings on her home, which she was able to stop, and faced a federal income tax investigation, in which she pleaded guilty to four misdemeanors and served 30 days in a halfway house.
Several voters who chose Chang-Díaz yesterday said that while they mostly agreed with Wilkerson on the issues, they could not forgive her ethical transgressions.
"It wasn't just a one-time incident; it was a pattern over time," said Dora Golding, a 33-year-old Jamaica Plain resident who voted at English High School. "I think she's been an effective state senator and probably in the next term would be more effective because of the experience and connections, [but] I felt that we don't have to settle for that. It's time to give a new voice a chance."
Michael Lake, a Chang-Díaz volunteer from Fenway and executive director of the World Class City Partnership at Northeastern University, said justice had been served with the results.
"Obviously our message for change and the voter's cry for integrity has rung out loud today," he said at a Chang-Díaz celebration at a Jamaica Plain restaurant. "I feel like I have a voice again in the State House."
Wilkerson supporters were dejected by the loss. Several said African-American and immigrant communities in the district, which stretches from the Back Bay and Beacon Hill to Roxbury, Dorchester, and Jamaica Plain, had lost a strong advocate.
"They have lost someone who works, who delivers to our community," said 62-year-old Shirley Shillingford of Roxbury. "There is nobody now who is going to be responsive to our needs."
Wilkerson backers at the polls explained their support by describing a kinship with her.
"She has stood up for our rights consistently over time," said Liat Wexler, a 30-year-old lesbian woman from Jamaica Plain who cast her vote yesterday at English High School. "I looked at Chang-Díaz, and I thought it might be interesting to have someone new in, but I looked at the history of what Dianne has done for us. I know her track record. I know what she's actually voted for."
Chang-Díaz could become the first Hispanic woman in the state Senate, said Giovanna Negretti, executive director of state Latino political organization Oiste. Another Hispanic woman, Sara Orozco of Needham, will face incumbent state Senator Scott Brown, a Republican, in the November general election, she said.
At her celebration, Chang-Díaz thanked Wilkerson for opening "doors for female leaders of color in our state Senate."
In the Fourth Middlesex Senate District, firefighter Kenneth Donnelly defeated former Arlington selectman Jack Hurd, 54 percent to 40 percent, in the race to replace former state senator James Marzilli, who resigned his seat. Marzilli resigned after being charged with groping a woman.
In the western suburbs, state Representative Pam Richardson of Framingham held off a challenge from two Democratic challengers, winning 38 percent of the vote. Chris Walsh had 35 percent, and Dawn Harkness had 27 percent with all precincts reporting.
Town officials were still counting late into the night as several write-in candidates from Watertown vied for the Democratic nomination for the 29th Middlesex District seat left vacant by long-time incumbent representative Rachel Kaprielian, who resigned after being appointed to head the Registry of Motor Vehicles on May 30. There is no Republican candidate for the November election.
The declared write-in candidates included Stephen Corbett, a Watertown town councilor who owns a construction firm; Julia Fahey, a labor lawyer for the Service Employees International Union; Jonathan Hecht, a Watertown town councilor and researcher at Yale Law School; and Joshua Weisbuch, a computer consultant.
State Representative Carl M. Sciortino Jr. apparently held off a challenge in his bid for reelection to a third term representing the 34th Middlesex District seat covering Somerville and Medford, even though he was forced to wage a write-in campaign after failing to file enough signatures to qualify for the ballot.
Sciortino said he received a concession call from Alderman Bob Trane.
"I feel incredibly humbled and grateful to the voters of Medford and Somerville," Sciortino said in a telephone interview last night. "I think today the voters showed that they reject negative campaigning and voted in favor of four years of accomplishments."
Globe correspondents Christina Pazzanese, Ryan Kost, and Jeannie M. Nuss contributed to this report. John C. Drake can be reached at email@example.com.