For years, no one could figure out what R.E.M.'s Michael Stipe was singing about -- not even the other guys in the band.

"I generally don't ask him. I don't want to know," said R.E.M. bassist Mike Mills. "I like whatever images and emotions I get from the songs. Like for most fans, it's about what it means to you, not what it means to Michael."

The last time Mills asked Stipe for an explanation was for "The Sidewinder Sleeps Tonite" in 1993. The explanation, Mills said, did not help. No such problems with R.E.M.'s new "Accelerate," a pedal-to-the-metal rocker that may be the best album of 2008. No decoder is necessary to decipher the meaning of these politically charged tunes.

"Mr. Richards" is about a corrupt politician who gets away with it. "Houston" is about someone who barely survived Hurricane Katrina. "Man-Sized Wreath" was sparked by President Bush's visit to Martin Luther King Jr.'s tomb in 2004. "I'm Gonna DJ" addresses the 1999 World Trade Organization riots in Seattle.

Why is the album so politicized? "You just have to look around you to answer that question," said Mills, 49. "The damage done in the last seven years is incalculable, and we're still pissed off about it. So that comes out."

But don't expect the Rock and Roll Hall of Fame band from Athens, Ga., to turn its concert next Thursday at Xcel Energy Center into a political soapbox in this election year.

"Given that it's important to us and to America, I'm sure we'll say something about it, but it's not going to be a focus. Hopefully, there won't be that much talking about anything," said Mills, though Stipe has worn a Barack Obama T-shirt onstage this year and endorsed the Democratic candidate.

The members of R.E.M. sometimes take their politics outside of the music realm. In 2006, Mills testified at a hearing in front of the Federal Communications Commission about media consolidation.

"It was nerve-racking, but I felt very empowered," he recalled of the testimony. "It's wonderful when you can talk directly to the people who have influence over the things you care about and you can tell them what you think."

However, he feels that his speech about radio conglomerates "taking the 'local' out of local radio" had no impact.

"They're still trying to do the same thing. [FCC chairman] Kevin Martin is still trying to further deregulate the ownership rules. Republicans will never change their stripes."

In 2004, R.E.M. released "Around the Sun," a disc the trio wasn't particularly proud of because it was "unfocused" as the band labored in the studio, Mills said. The album has sold only 250,000 copies, by far the slowest seller in the band's 14-disc catalog.

For its followup, R.E.M. took a more accelerated approach. "We wanted the songs to be short and loud. We wanted the record to be short and loud. And we wanted the time spent in the studio to be minimal," Mills said succinctly.

With 11 songs clocking in at a mere 34 minutes, the scorching "Accelerator" "feels like a vinyl record. It's under the time limit for vinyl," Mills said. "When I picture it in my head, I picture a vinyl LP, and I can't say I've done that with the others."

R.E.M. has certainly rocked out before, notably on 1994's "Monster." Mills thinks the band was ready to do it again partly because the last couple of tours with new drummer Bill Rieflin, who signed on in 2004, "had gone so well that we felt more like a band than we have in a long time." (Founding drummer Bill Berry retired in 1997.)

Speaking a few days before tour rehearsals were to start, Mills predicted the band would play most of the material from the new album and dust off some oldies. Stipe, Mills and guitarist Peter Buck will have to relearn the oldies just like Rieflin has to learn them.

"Bill can learn as many songs as required," the bassist said. "He can play his own style or he can play what Bill [Berry] used to play with equal facility."

And Stipe even has to study his own lyrics.