Attorney General Martha Coakley, who only three years ago appeared to be finished politically, will join the race for governor with an announcement in her hometown of Medford on Monday followed by an 18-city barnstorming tour for the next three days, a top Coakley political aide said.
Her campaign will test whether Democrats are ready to take another chance on her leading the ticket next year as she emphasizes a theme of expanding economic opportunity, job creation, and improving education.
“Massachusetts is poised to take off,” Coakley said in a statement she released Sunday. “We can either grab this moment and move forward together, or risk falling behind. I believe we must continue to rebuild our economy in a way that gives everyone the opportunity to succeed, and launch new education reforms so that every child and adult has the skills they need to compete in a global economy.”
She will release a video announcement Monday morning and begin her day at Dempsey’s Breakfast and Lunch in Medford, before heading to Brockton, Attleboro, Fall River, New Bedford, and Hyannis for her first day of campaigning.
Despite a lackluster performance that led to her humiliating loss to Scott Brown in the 2010 US Senate race, Coakley is expected to be a formidable candidate in the primary. Recent polls show she is now one of the most popular political figures in the state.
She joins a Democratic primary field that includes one other woman, who has never run for office before, and three men — including the candidate many analysts consider her main rival in the early stages of the campaign, state Treasurer Steve Grossman.
Grossman, a former state and national party chairman, has been working hard for several years, crisscrossing the state and button-holing party leaders, fund-raisers, and activists for support. Coakley, who was expected until this spring to run for reelection, for the most part has not circulated among the party activists, keeping a low profile politically while focusing on her job as attorney general.
Grossman released a statement Sunday that takes a direct shot at Coakley’s emphasis on economic issues. “I am the only Democratic candidate who offers a lifetime of proven leadership in strengthening our economy,’’ he said.
Still, with her high-profile work as attorney general in the last few years boosting her image, early polls show Coakley leading the pack in the party primary and running the strongest against probable GOP nominee Charles D. Baker.
She faces skepticism within the party rank and file, however. Based on the 2010 Senate race, many party regulars are concerned about her ability to sustain a strong campaign in the general election.
Analysts say the question of whether Coakley can win the governor’s office depends on her using the tough lessons learned from the Senate race. Her supporters point to her ability to rebound as evidenced by her landslide reelection victory later that year.
“You can tell a lot about someone’s character not when things are going well, but when they have a setback,” said state Representative Paul Brodeaur, a Melrose Democrat. “That says more about her than anything else.”
Peter N. Ubertaccio, director of the Martin Institute at Stonehill College, said Democrats would make a mistake to view Coakley “exclusively through the lens of January 2010.’’
“She turned around immediately from that defeat and was reelected by a substantial margin and has continued since to remain one of the most popular politicians in the state,’’ he said. “A lot of it depends on whether she and her people have learned from that Senate campaign.’’
Mary Anne Marsh, a Democratic strategist who is not affiliated with any campaign, said the decision to launch her campaign in a three-day tour through the state — compared to the recent video release by Baker — shows Coakley is serious about retooling her image as an aloof prosecutor.
“The fact that she is doing an 18-city tour shows that she is intent to put those doubts aside and the past behind her,’’ Marsh said.
Coakley, who is convinced her failure in the Senate race was due in part to a poor campaign structure, has also turned to campaign strategist Doug Rubin, who many consider the party’s top political adviser in the state. His past list of clients includes Governor Deval Patrick, Senator Elizabeth Warren, and Representative Joseph P. Kennedy III.
Her arrival in the already crowded Democratic field comes as another major potential rival, US Representative Michael Capuano, the Somerville Democrat, is close to a decision on whether to run. He has lined up financial support, staff, and consultants but has yet to make a final determination.
“We always anticipated this would be a crowded primary and clearly it will be very crowded primary,’’ said Paul Trane, a longtime senior adviser to Capuano. He said Capuano will make a final decision in the next several weeks.
One of Coakley’s strongest advantages is support she is getting from Democratic women activists and fund-raisers, who had encouraged her to jump into the race. Until that pressure mounted this spring, members of her inner political circle signaled that she would probably not run and instead seek a third term as attorney general.
Emily’s List, a Washington-based political group with a mission to elect women to public office, is expected to provide Coakley significant financial resources through its national fund-raising network.
The other woman in the Democratic race is Juliette Kayyem, a former Globe editorial page columnist who has served as a state and federal homeland security official. Kayyem said last month she would run, although she had indicated earlier she would not get in the race if Coakley entered.
She said Sunday she would not bow out because of Coakley’s entrance, contending she had joined the race in August convinced that the attorney general would also run and with the view that women should compete in politics.
“It’s the 21st century, so the era of one woman at a time is long gone,’’ said Kayyem.
Still, with no electoral experience and little name recognition, Kayyem faces up an uphill battle to get herself into serious consideration, particularly if Coakley is in the race.
Also running is Don Berwick, who ran Medicaid and Medicare in the Obama administration, and Joseph Avellone, a biotech executive.
Coakley’s decision will add to the political free-for-all that continues to develop for the 2014 state campaign. State Representative Daniel P. Winslow, a former district court judge who lost his primary bid to be the GOP candidate for US Senate earlier this year, has said he will make an announcement about his plans on Monday.