It turns out that Damon is seriously patriotic—not the chest-thumping, America-is-the-strongest-country-in-the-world kind of patriotism but the kind that allows for criticism of U.S. policies when they seem wrong but that believes in the generosity and good which Americans can do. His recent films—Syriana, about U.S. oil interests and corruption in the Middle East; The Good Shepherd, which raises questions about the ethics of a patriotic CIA agent; and Green Zone, which will come out next year, about U.S. involvement in Iraq—have explored America's policies with a critical eye. And yet he speaks with admiration—and knowledgeably—about PEPFAR, President Bush's $15 billion AIDS initiative in Africa, as well as the $698 million aid package the United States recently gave to Tanzania.

Damon says he hopes the next president will urge a new era of service in America. He is encouraged that both John McCain and Barack Obama have promised to travel to Africa and step up aid to the continent. "We are about to turn a wonderful corner and close this chapter of aggression, where the only American face that people see on foreign soil is the face of a soldier," Damon says. "As well-meaning as that soldier is, that sends a certain message. But when you go to a country and see your fellow Americans feeding people or getting clean water or saving their lives, you are really seeing the best of us. We are exporting the best of who we are—and who we should be."

I am impressed. I knew that Damon was committed, but we live in such an age of cynicism that I don't exactly expect Hollywood stars to talk about their desire to stand up and serve their country. But here is Matt Damon, as canned music plays in the background at this Midwestern hotel restaurant, telling me he hopes that the next president will use Hollywood activists "in a more organized way." So do we need all these celebrities running around saving the world? Maybe our cynicism is misplaced. After all, Damon's H2O Africa Foundation has brought safe drinking water to millions of people. Clooney and Cheadle have raised awareness of the violence and poverty in Darfur. Pitt and Angelina Jolie are rebuilding large sections of New Orleans. Even "Idol Gives Back," the slickest use of fame for global causes in history, raised an astounding $76 million for African and American charities last year. And in the process, the celebs have inspired us to contribute and to take action, too. What could be bad about that?

Maybe I'm just intoxicated by this dreamy movie star chatting with me as if we were just a couple of policy wonks, but by this point my journalistic skepticism has all but evaporated. A black SUV is waiting outside, ready to drive Damon back to the set. We exchange e-mail addresses, and he tells me to keep in touch. With that, the water crusader heads off to his day job: Hollywood idol.