Democrats gather to hear 'rock star' Bill Clinton

Coakley, the state’s attorney general, is facing a tough challenge from Republican State Senator Scott Brown, who was little known until this race but who appears to be surging in some polls. A Suffolk University poll released Thursday suggested the two candidates were in a statistical tie, with Brown holding a 50-46 percent edge, with a margin of error of 4.4 percentage points. Independent Joseph L. Kennnedy is also in the race.

Coakley's rally drew an assortment of Democratic operatives, elected officials, and fans of the former president. The free event was held in the glitzy Grand Ballroom, with two additional rooms to handle an overflow crowd.

Supporters waved Coakley's campaign signs, and there was an army of reporters, cameramen, and photographers from around the country in a roped-off area.

Massachusetts Senator John F. Kerry, the 2004 Democratic nominee for president, who attended the rally along with Governor Deval Patrick, said the race was crucial.

"The voting here is going to determine the balance of power in America, and with it, it is going to determine the fate of what we started with Barack Obama a little over a year ago," Kerry said.

Coakley took the stage last, repeating many lines she has used on the campaign trail. But she unveiled a new one that brought the loudest cheers from the crowd.

"Just because you drive in a truck doesn't mean you're going in the right direction," Coakley said, referring to Brown's claim that he drives an old truck with 200,000 miles on it.

In Worcester, later in the afternoon, several hundred people, most of them students, packed a hall at Worcester Polytechnic Institute, to hear Clinton and US Representatives James McGovern and Richard Neal deliver impassioned pleas for Coakley.

The raucous crowd turned quiet as Clinton, with Coakley at his side, assailed Brown as an agent of obstruction whose election would enable the Republicans to block health care reform through a filibuster.

"I can't believe that the birthplace of America would want to be the birthplace of paralysis," Clinton said.

Coakley will also get a big boost Sunday with a visit from President Obama. Her campaign said today she was beginning a four-day tour, which would run Friday through Monday, the day before the election, and include 20 stops.

Brown, meanwhile, campaigned this morning with former New York City mayor Rudolph Giuliani in the North End. A feisty crowd of several hundred chanted "Rudy, Rudy" and "Go, Scott, Go."

Bill Clinton is very popular in Massachusetts, a state his wife, Secretary of State Hillary Rodham Clinton, won in her primary campaign against President Obama.

“Bill Clinton is a rock star in Massachusetts,’’ said US Representative Edward Markey, Democrat of Malden, predicting that the last-minute surge of national Democratic help will seal the election for Coakley. “The Democratic base now has the activating fluid’’ to get out the vote, he said. “ The Democratic activists are now up and working, energized, and ready to go.”

Brian MacQuarrie, Susan Milligan, and Martin Finucane of the Globe staff contributed to this report.