Evangelical writer Rick Warren's latest sermon is on AIDS prevention. At a recent AIDS confab in Toronto, Warren, author the of the bestselling "The Purpose-driven Life" (Zondervan, 2002) announced that the "Church needs to take the lead in the greatest health concern on the planet" -- causing some to dub Warren the leader of an upcoming AIDS "reformation."

What Warren is doing is divine, but not entirely new. He's putting a purpose-driven spin on the simplest idea: "abstinence, be faithful and condoms" (ABC) -- to replace the old, hasn't-quite-worked approach -- "safe sex" -- with a much more promising strategy for saving at-risk people in Africa, and everyone else whose activities are liable to expose them to HIV.

Truth is, there's nothing mysterious about AIDS prevention. The ABC approach is the one that has shown results. As Harvard researcher Edward C. Green has phrased it, "Uganda rocked the world of AIDS prevention by promoting 'sticking to one partner' and delaying the age of first sex." He wrote earlier this year: "The broad trend in Africa is in fact toward higher levels of monogamy, fidelity and abstinence, and the trend in HIV prevalence is incrementally downward. We now see HIV prevalence decline in Kenya, Zimbabwe, Senegal and probably other African countries as well." Seeing a winner, the Bush administration has based its own program for AIDS prevention in Africa on this ABC approach. Green, who knows Rick Warren and his wife, Kay, (and will be speaking at their conference in November), tells me from South Africa that the message Warren has embraced is the key: "no sex outside of marriage ... if both partners follow this, we will 'stop AIDS.'"

Warren seems to thoroughly get that. He talks about "transformation": "That involves saving sex for marriage, training men to respect women, offering treatment through churches, and encouraging individuals to pledge themselves to one partner." And while this is an old-school teaching, it also has the potential to be revolutionary. Whether you're a Kenyan or a Bostonian, that's how real change happens.

Folks on all sides of contentious issues -- especially sex -- know that Christianity has tremendous influence on hearts and minds, which is why Church leaders are often subjected to brutal rhetorical assaults. When AIDS comes up in elite company, the discussion will inevitably turn to the dangerous influence of the Catholic Church, because it doesn't condone condom use. One British editorial earlier this summer declared, "The Pope should slow the spread of AIDS." The editorial acknowledged that the Catholic Church runs "a quarter of the world's AIDS treatment centers," yet still admonished it to abide by the commandment "Thou shalt not kill" (i.e., embrace condoms or people will die, is their argument).

Warren could help change things: The popular preacher claims "a network of tens of thousands of churches from all denominations in 160 countries." As a preacher, he's a bit of a teddy bear -- a regular guy who even talks about how he's uncomfortable pontificating. He's a fresh, kind and gentle face without centuries-as-a-dart-board baggage. He talks, first and foremost, about loving your neighbor. He's even got a friendly acronym for the fight -- "C.H.U.R.C.H.: Care for and comfort the sick; Handle testing and counseling; Unleash a volunteer labor force; Remove the stigma; Champion healthy behavior; and Help with nutrition and medications."

Cheesy, soft-serve, pop religion? Maybe. But he's got his heart in the right place and has latched onto the right evidence and isn't setting out to reinvent the wheel. Wendy Wright, president of Concerned Women for America, sees Warren's star-power entrance on the AIDS-prevention scene as only natural: "When the glamour of AIDS activism fades and fatigue sets in for lack of success because of failed policies, Christians will still be toiling. It is likely that they will rise as the leaders, perhaps because the pool will become smaller, but more importantly because they're providing the solutions that work."

And, working with the Global Fund for AIDS, Warren seeks to bring government and Hollywood money along with the faithful on the ABC journey. You don't have to sing in the same theological chorus as Warren or even buy his book to give him an "Amen." If Warren can get Bill Clinton, Angelina Jolie, Bill Gates and Kofi Annan cooperating with, say, the Catholic Church and a myriad of other faith-based servants in doing what works -- changing behavior -- well, preach it, brother!