It's been a tough stretch for Elizabeth Warren, the Democratic Senate candidate and liberal darling.

In late August, a new poll showed Warren falling five points behind Scott Brown, the Republican incumbent. Meanwhile, Brown's seeming ability to out-maneuver Warren has prompted a rash of skeptical  assessments. The conventional wisdom, at this point, is that her political instincts are questionable and her campaign is in trouble. 

According to Warren, though, nothing could be further from the truth.

"You know," Warren told WGBH during a September 10 visit to the Lexington Fire Department, "I feel the enthusiasm growing."

Since her speech at last week's Democratic National Convention, Warren added, her campaign has been deluged by individuals eager to support her candidacy.

"Since I spoke in Charlotte," Warren said, "we've had 2500 new volunteers in the campaign signing on, saying, 'I want to be part of this.' And that's been a big part of this, has been the grassroots. People who come into the campaign offices — we now have 33 offices open around the state — and say, 'I hear the message. I want to be part of helping you win."

The Warren campaign did not immediately provide its total number of volunteers.

During Warren's Lexington visit, she cast herself as a supporter of first responders such as firemen and police officers. In 2011, Warren said, Brown let down those groups down by backing the filibuster of the Democrat-supported Teachers and First Responders Back to Work Act. 

"There was a bill in the United States Senate that would have prevented the layoffs of teachers, firefighters, police officers, and other first responders all across this country," Warren said. "Scott Brown voted no. I would have voted yes."

The Brown campaign was not immediately available for comment.

UPDATE: In an emailed statement, Brown campaign spokeswoman Alleigh Marre said: “Only in Washington D.C. or the faculty lounge at Harvard does it make sense to raise taxes to create jobs. Professor Warren’s $3.4 trillion tax hike would destroy jobs and crush our economy. Scott Brown was proud to support bipartisan legislation to provide care for the brave first responders on September 11th who unselfishly risked their lives when our nation needed them the most.”

Marreigh seems to be referring to the James Zadroga 9/11 Health and Compensation Act, which passed the Senate in December 2010. It created a $4.3 billion compensation fund for first responders who were injured or sickened as a result of the September 11, 2001 terrorist attacks.