Lt. Gov nominee Steve Kerrigan, Gubernatorial nominee Martha Coakley and Senator Elizabeth Warren outside Coakley campaign HQ (WMassP&I)

SOMERVILLE—The most coveted endorsement this election cycle anywhere in the country may be Massachusetts’ own senior Senator. Elizabeth Warren’s backing of Attorney General Martha Coakley may have been a foregone conclusion. Still, the one-time law professor’s formal backing of the Democratic gubernatorial nominee Saturday energized the activists and supporters, crowded into the very campaign office from where Warren’s own campaign operated in 2012.

The weekend after the competitive Democratic primary for the open statewide offices in Massachusetts, Coakley and her newly minted lieutenant governor nominee Steve Kerrigan, crisscrossed the commonwealth ginning up support from her primary opponents’ partisans and assuring uneasy Dems of her commitment and drive in this race.

Indeed on the same Saturday Warren rallied Democrats here, Coakley took part in one of her former rival’s favorite campaign activity and invoked one of the slogans of her other primary opponent.

The crowd in Coakley HQ before Coakley and Warren arrived. (WMassP&I)

Inside the stuffy first floor quarters of Coakley’s campaign headquarters in a nondescript office building near Assembly Square, Coakley, Warren and Kerrigan enjoyed a rockstar welcome from dozens of supporters. This was Coakley’s fourth public event of the day after an event with Treasurer Steve Grossman, two appearances in Springfield and another in South Boston where she ran into her former neighbor (and one-time rival) “Mahty,” Boston Mayor Marty Walsh.

Warren acknowledged Grossman and Dr. Don Berwick’s campaigns and contribution the primary, “We were blessed to have great candidates.”

Earlier in the day Coakley attended the State Committee meeting in Springfield, where Senator Ed Markey and Rep Richard Neal showered praise on her. Grossman, too, egged on to speak by the cheering committee members, took the podium to urge his supporters to get behind Coakley.

Sen. Warren ran her campaign out of the same ground floor office near Somerville’s Assembly Square. (WMassP&I)

Noting her own campaigns use of the same office, Warren offered another connection to the attorney general. Eight years ago, Warren recalled, she was just a law professor. “That’s all I was going to do was teach do research and…fight!” she said, prompting another round of raucous applause.

Warren had been writing books and giving speeches about how regulators seemingly always tilted toward the powerful in society. One day her phone rang, “I got a call from a woman who introduced herself as the new attorney general for commonwealth.”

“She said ‘I’ve been reading what you do. How can we work together?’” Warren recalled from that conversation. “‘Let’s talk about how we can help level the playing field just a little bit for our families,’” she said Coakley told her. Since that call, Warren said Coakley “led a revolution” of attorneys general to fight back against those who were foreclosing on homes.

Warren with supporters (WMassP&I)

Warren also took a moment to recognize Deb Goldberg, the party’s nominee for Treasurer and Maura Healey, nominee for attorney general. “We are going to be 100 percent behind” her, Warren boomed, having endorsed Healey in Lawrence earlier that day and did the same for Goldberg the next day.

For her part, Coakley thanked Warren for being a “champion” for middle class causes and alluded to the “fairness” mantra of her campaign, “We can be prosperous and fair!”

As she had earlier in Springfield, Coakely also thanked her Democratic primary opponents, noting the morning scoop of ice cream that she and Grossman shared in Newton. She also invoked her other rival a bit more directly, perhaps an appeal to his supporters. “As Don Berwick says, ‘all means all!’” Coakley roared to thunderous cheers.

Her running mate, Kerrigan, spoke as well, briefly imploring supporters to give their time to get the ticket elected. “If you give us 52 days,” he said, “we will give you four years like you’ve never heard of.” The Coakley campaign is mulling how best to utilize Kerrigan, who join Coakley on the ballot, after being nominated separately. Short term strategy, sources say, may include outreach to central Mass towns, like Kerrigan’s native Lancaster, which have slipped away from Democrats in recent years.

Martha Coakley addressed supporters. John Walsh is behind her right arm and Steve Kerrigan and Sen. Warren are to her left. (WMassP&I)

Alluding to Republican nominee Charlie Baker’s recent adoption of a nice guy of a personality John Walsh, the former chair of the state Democratic Party, said if Democrats hit the doors and the phone hard they will leave Baker with much less to be happy about. “It is true that Charlie is smiling more these days,” Walsh, who currently head Gov. Patrick’s Together PAC, “if you do the work we will wipe that smile right off his face.”

But it was Warren who both raised the stakes and challenged the supporters and volunteers to make it happen.

“It never in a million years crossed my mind that there would be a day when we would have a chance to work together as senator and governor,” she said. “We’ve got that chance! What I’m counting on, is the people in this room are going to make it happen.”