This tour has been a bit of a love fest," says U2 frontman Bono, sounding genuinely humbled and slightly surprised that a tour by one of the most celebrated bands in the world in support of one of its most acclaimed albums in years would generate any sort of affection at all. "I've nearly wept reading some of the reviews of the shows, they've been so effusive." He pauses and smiles. "It's just great being in this band at this minute."

There have certainly been other great moments to be in U2 over the course of the past two decades. The band's previous outing, the Popmart tour—when the boys from Dublin appeared in a huge onstage lemon and got pelted by (metaphorical) rotten fruit by critics in the U.S.—probably wasn't one of them. But their latest CD, All That You Can't Leave Behind, which was released last October, went to No. 1 in 32 countries, won the band three Grammys and helped spark an acclaimed, sold-out tour. Building on the fresh momentum, U2 is gearing up for a new series of U.S. shows this fall. Forget the lemons. This time the band is making lemonade.

With the new album and tour, U2 has left behind the techno trappings of 1997's Pop for straight-on, earthy, lusty rock 'n' roll. "Our last albums were in a way deconstructing what a band was about," explains drummer Larry Mullen. "It's great to be playing as a real band again." U2 is also excited about being able to connect with an audience in an intimate way again. "People have been coming to U2 shows for 20 years now. It's almost like the Deadheads at this stage," explains bassist Adam Clayton. "People realize that it's about them as well as us."

It's also about politics. What's most surprising about U2's comeback is that the band hasn't toned down its idealism to fit today's junk-rock, glam-rap times. In fact, the performers have amped it up. During the North American leg of the Elevation tour, the band showed footage of Charlton Heston defending his views on firearms followed by stark footage of a small child playing with a gun and violent scenes from Vietnam as a sarcastic introduction to the song Bullet the Blue Sky. The new album, All That You Can't Leave Behind, takes its title from a song dedicated to the Nobel Peace Prize-winning Burmese resistance leader Aung San Suu Kyi, and the liner notes urge fans to remember victims of Sierra Leone rape and war crimes and to support Amnesty International, Greenpeace and the children's charity War Child. These aren't topics you'll hear addressed at, say, a Limp Bizkit show.

U2's political roots are planted in Irish soil. "We were never not going to be a political band," says Mullen. "In the rest of the world, the two things that you can't talk about are religion and politics. In Ireland the only things we talk about are...religion and politics. I also think that real rock 'n' roll has always been tied up in political issues, and you can't separate it." U2's guitarist, the Edge, agrees: "Political music can turn you on to things. It's always been that way for me. Jimi Hendrix, the whole kind of Vietnam antiwar movement was a turning point for America. No matter what's been going on, there's always been rock 'n' roll around the world of politics and social movements, in and around it. In that sense we've just attempted to do with our music what in the past we've picked up from other music—the kind of music that's alive and relevant, that's politically aware, socially aware. That's the only music that we are interested in making."

The band members, however, are wary of crossing the line from performers to preachers. They understand that taking a political stand is usually viewed as the act of a band desperately trying to be cool. "It's just so unhip to be talking about debt relief," says Bono, discussing his passion of the past few years. "The band has been really supportive about giving me the time to work on this." He first became interested in Africa's economic plight in the 1980s, after the Live Aid concerts that raised money for Ethiopian famine victims. "My wife Ali and I ended up going to Ethiopia for some time doing relief work. We were so high on the idea that Live Aid raised $100 million—and then you discover years later that that's what Africa pays every couple of weeks on old loans. It's kind of a shock. I thought we'd never forget what we'd been through in Ethiopia, but you go back to your life and then those images just fade away."

The images may have faded, but Bono's curiosity did not. In 1999, the singer got involved with Jubilee 2000, now known as Drop the Debt, a London-based coalition of academics and activists who equated Third World debt with slavery. In the course of his work with the campaign Bono has met with Presidents, Prime Ministers and the Pope to get attention for the issue. He relishes the incongruity of a rock star talking about world policy, but he backs it up by knowing his stuff. He reads economics tomes and did some unofficial studying at Harvard. "I think that politicians are attracted at first by the celebrity," says Harvard economics guru Jeffrey Sachs, who has huddled with Bono and the Pope on the debt issue. "But once they meet him, they find that he is an outstandingly capable interlocutor." Senator Jesse Helms met with Bono to talk about starving children in Africa and ended up weeping—marking the first time a rocker has inspired an emotion in the Senator from North Carolina other than perhaps outrage.

So, can rock change the world? The image most of the public has of rockers is that of drive-by dilettantes who throw money at a problem and then limo off to the next gig. U2 is taken more seriously because it has lasted longer than almost every other rock act on the scene—so its commitment to social causes seems, well, more committed. "Rock music can change things. I know that it changed our lives," says Bono. "Rock is really about the transcendent feeling. There's life in the form. I still think that rock music is the only music that can still get you to that eternal place where you want to start a revolution, call your mother, change your job or change your mind. I think that's what rock music can do."