Lexington Democrats liked what they saw last month when Elizabeth Warren visited with a group of activists last month during a stop on her statewide listening tour. 

Warren, a Democrat and consumer advocate, is expected to officially announce today that she'll enter the race for the right to challenge Republican Scott Brown for the US Senate seat he's held since his surprising win in the 2010 special election.

A Warren spokesman told the Associated Press a formal announcment will come today, Sept. 14, but local dems have been awaiting the news since Warren impressed at a private residence on Aug. 16.

“I think she’s the first candidate on our side who has really excited the activists, and I think that’s a great thing," Robert Peters, co-chair of Lexington's Democratic Town Committee, told Patch columnist Denise Dubé at the time. “I thought she was very impressive with the range of experience she’s had both in Washington and fighting for middle class men and women, against a financial service sector that has failed us all."

National activits feel the same as Peters, according to the Huffington Post, which reported party leaders believe Warren, a Harvard professor and Obama advisor, would be the toughest opposition for Brown, who upset Attorney General Martha Coakley in 2010.

Speaking with Patch last month, Peters said he was moved by Warren's focus on the middle class, something she stressed in a statment obtained the HuffPo.

“The pressures on middle class families are worse than ever, but it is the big corporations that get their way in Washington,” said Warren, in a statement obtained by The Huffington Post. “I want to change that. I will work my heart out to earn the trust of the people of Massachusetts.”