What was that about a Democratic “enthusiasm gap”?

Whichever pollster coined that phrase neglected to consult with the citizens converging last week on the International Brotherhood of Electrical Workers union hall here. They filled the parking lot, then the one next door, then the one across the street.

“I couldn’t contain myself when I heard she’d be here,” said Matt Szafranski, a blogger at the event.

“I’ve already donated twice, and I’m looking to go to a rally,” said Fran Miffitt, a retired nurse.

By the time the candidate arrived for the meeting – a prosaic organizing session for volunteers — there were nearly 300 people crammed into Local 7 to catch a glimpse of her. When she took the stage, a sea of cameras and smartphones rose, as if at a rock concert.

All this for a law professor who specializes in contracts? But Elizabeth Warren, the former adviser to President Obama who is now trying to unseat Republican Sen. Scott Brown, is no mere professor, or candidate. She is a phenomenon.

The source of the ardor is no mystery: Warren’s unapologetic populism and her fervent belief that corporations should be held to account for the economic collapse. Part Pat Moynihan, part Erin Brockovich, she has revived the energy of the left in a way no other Democrat has, including President Obama.

“We live in an America that has hammered, chipped and squeezed the middle class,” she told a crowd in Newton, Mass., while the government “has said to large corporations that you don’t have to pay anything in taxes.”

“Elizabeth,” a woman in the crowd gushed during the question time, “I’m so excited.” But what, the woman asked, would Warren do about the dysfunctional Congress?

Warren recounted her work creating Obama’s Consumer Financial Protection Bureau in defiance of “the largest lobbying force ever assembled on the face of the earth.” Instead of heeding advice to settle for “something at the margins,” Warren said, “my view on this was [to] get out there and fight for it.”

The questioner could not contain herself. “Yes!” she cried out.

Warren is the first candidate of the Occupy Wall Street movement, the liberal equivalent of a Sarah Palin or a Jim DeMint. She has tapped the enormous anti-corporate resentment on the left and become a lightning rod for the right.

In her first few weeks as a candidate, she raised well over $3 million from more than 11,000 people — more than double the amount raised all quarter by the incumbent Brown. All serious competitors have dropped out of the Democratic primary, and polls show her neck-and-neck with Brown.

Warren has no interest in going to Washington to be “slow and polite,” she told me. She wants to go to fight corporate excess, because “the people who brought us the financial collapse have now doubled down” by resisting attempts to re-regulate business.

“The idea of going to the Senate to be the hundredth least senior person in a nonfunctional organization is not what attracts me,” she said. “I see going to the Senate as an opportunity to expand the platform” and as a way of “leading the charge.”

That’s a good thing and a bad thing. Bad, because it means Democrats are beginning to embrace the Tea Party notion that Washington should be a place of polarization and warfare. Good, because it means Democrats will no longer play by Marquess of Queensbury rules while their opponents disembowel them.

For better or worse, Warren’s fighting ways are more successful than Obama’s in generating enthusiasm. Obama, she says, “is much cooler than I am.” And what dispirited liberals are looking for is heat — somebody who believes, as Warren often puts it, that “some fights are worth having.”

That’s what brings her supporters out by the hundreds. “You got to have somebody to fight,” said University of Massachusetts student Patrick Kenney. “We need to go up against the big boys: I hate corporations,” said Joanne Burke, at the Newton event.

Warren, who describes herself as “a maintenance man’s daughter [who] made it to be a fancy-pants professor at Harvard,” has been too impressed with her own success; she had to walk back a claim that she “created much of the intellectual foundation” for the Wall Street protest movement.

But clearly she has found a way to rally the left. Would other Democrats, including Obama (who tried to placate Republicans and business interests but still got branded a socialist), be in a better place if they followed her populist model? “I’m going to take a pass on that question,” Warren told me.

That’s okay. The answer is obvious.