Discarding his long-held distaste for the harsh world of US party politics, Springsteen joined forces and voices with REM at a concert in Philadelphia late on Friday that sought to mobilise voters in advance of November's presidential election.
"We're here for a purpose, we're here for a reason," Springsteen told the sell-out crowd that at times seemed torn between adoration of their idol and acceptance of his new-found political persona.
The 55-year-old rock legend, who has acknowledged his discomfort with adopting a partisan role, offered a self-deprecating take on his campaign message.
"And now the moment you've all been waiting for," he said halfway through a blistering set with his E Street Band. "My public-service announcement."
Vote for change
Underlining his opposition to the war in Iraq with a call for the United States to show humility in "exercising its power at home and abroad", Springsteen urged the crowd to help bring out voters on 2 November.
"The best way to express your concern is to roll up your sleeves and do something," he shouted, before launching into a raucous version of his classic standard Born to Run.
The show kicked off a 10-day series of Vote For Change concerts in a dozen battleground states across the country with acts like Pearl Jam, the Dave Matthews Band, Bonnie Raitt, the Dixie Chicks and Sheryl Crow.
"The best way to express your concern is to roll up your sleeves and do something"
The Philadelphia bash was just one of half a dozen given across the state of Pennsylvania on Friday night, with the proceeds going to Americans Coming Together (ACT) - a voter-mobilisation group seeking to build support for Bush's challenger, Democrat John Kerry.
Springsteen has always enjoyed a loyal following among both
Democrats and Republicans and his emergence as a party activist has been the subject of heated debate on fan websites, with some saying they felt upset and even betrayed by the move.
But Fred Norrell, 30, from New Jersey, argued that the critics
were simply showing their ignorance of Springsteen's well-documented social activism.
"He's been political all the way down the line. People who are
Many in the concert's audience
sported 'Run for Kerry' T-shirts
complaining are either deaf, blind or both," Norrell said. "If they don't like it, they shouldn't be here."
Amee Curley, 28, from Virginia, who confessed to being "unsure" about Kerry, said several Republican friends - also "hardcore" Springsteen fans - had tried to persuade her not to come.
"They've been e-mailing me asking if I'll be attending political
sit-ins next," Curley said. "But I'm here for the music and I think they'll come around eventually. They're not burning their discs or anything."
Tom Rutherford, 35, from New Jersey, said he admired Springsteen for coming out of the political closet, but added that he had made up his own mind about the election a long time before "The Boss" called for the president to be sacked.
"I'd vote for my cat if he was running against Bush," Rutherford said. The T-shirts at the concert confirmed the Democrat-leaning demographic, with messages ranging from "Bush Must Go!" to "Run For Kerry" and the optimistically loyal "Bruce For President."
REM provided a stellar support act, with frontman Michael Stipe describing the coming election as "a very important moment for every one of us and our country".
"I'd vote for my cat if he was running against Bush"
resident of New Jersey
And in an ironic nod to the TV campaign advertising spots
endorsed by the presidential candidates, Stipe paused between songs to announce: "We are REM, and we approve of this concert."
And so did the fans, even if politics was not always the prime
motive for their attendance. "To be honest, we're not getting a great response," said Rosa Rodriguez, an ACT activist trying to sign up volunteers outside the concert hall. "A lot of them just aren't that interested, but we're being persistent."