(FORTUNE Magazine) – After Hurricane Katrina hit, Rick Warren was one busy pastor. He traveled to Houston to preach to 8,000 evacuees in the Astrodome, standing in a skybox next to Oprah Winfrey. He went on the Larry King show to explain how churches were stepping in to do relief work. He lobbied his friends in the White House to release disaster-aid money to religious groups. And in case anybody missed his post-hurricane tour, his publicist issued a press release when it was done.

In part by campaigning for the job, Warren, the 51-year-old Southern California pastor, bestselling author, and management genius, has become secular America's favorite evangelical Christian. This year he has spoken at Harvard, Oxford, Cambridge, the Aspen Ideas Festival, the Young Presidents Organization, a Pew Foundation forum for religion writers, and the University of Judaism. (The rabbis wanted to get his advice on how to increase their market share.) He has gone before the Council on Foreign Relations to pitch his newest idea: a breathtakingly ambitious project to mobilize American Christians to fight poverty, illiteracy, and AIDS in Africa.

A protégé of management thinker Peter Drucker, Warren is also cultivating corporate executives. He calls himself Rupert Murdoch's pastor, he has entertained Jack Welch at his home, and he will meet Bill Gates at a Time magazine conference on global health, where they are both scheduled to speak. He also has forged ties with celebrity activists like Bono, who arranged to make him official pastor of the Live 8 concert last summer in Philadelphia. ("The only thing I remember about that concert is Linkin Park and a sweet smell in the air," Warren joked to his congregation.) If a middle-aged Baptist minister can be said to possess that elusive quality called buzz, Rick Warren has it right now.

Several factors explain why. One is the clout of evangelical Christians. They now number some 30 million to 50 million Americans, and their overwhelming support for George W. Bush, a fellow evangelical, helped him win reelection last year. (Warren sent a letter to 150,000 pastors, in effect urging "those of us who accept the Bible as God's word" to get out the vote for Bush.) Harriet Miers, Bush's embattled nominee for the U.S. Supreme Court, will be the first evangelical Christian to sit on the court if she is confirmed. Warren emerged from the pack of evangelical leaders because his book, The Purpose-Driven Life, has sold 26 million copies since it was published by Zondervan, a unit of Murdoch's News Corp., in 2002--making it one of the decade's top sellers, up there with The Da Vinci Code. He has also set himself apart by putting a friendly face on a movement that scares a lot of people with its positions on issues like abortion and gay rights. Warren shares those absolutist positions--he believes homosexuality is a sin and Jews will go to hell--but doesn't emphasize them. (For more on the culture wars, see the following story.)

Most of all, Warren gets attention because he is, as he likes to say, a "spiritual entrepreneur." Using techniques that he learned from Drucker, among others, Warren built Saddleback Valley Community Church in Lake Forest, Calif., into one of America's biggest religious institutions. "Forget any opinions you have about religion and just look at the guy as a CEO, and you've got to be impressed," says Joe Ritchie, a Chicago businessman and Warren ally who once ran the world's largest options-trading company. Today Saddleback has an annual budget of $30 million, 300 employees, a 120-acre campus, and around 22,000 worshippers each weekend. Warren also founded Purpose-Driven Ministries, a nonprofit network of about 150,000 pastors, which has its own staff of about 180 people, a $39 million budget, and a thriving website called pastors.com. Its members may be Baptist or Methodist or Episcopalian, but they use his system. Call it open-source evangelism. "We're kind of the Linux of Christianity," Warren says.

Warren is a new brand of evangelical leader--an affable baby-boomer who is savvy about business, comfortable in the mainstream culture, and eager to build coalitions around his major concerns. Because he would like hard-line churches to play an even bigger role in national and global affairs, he wants to soften the image of evangelical Christianity--which leaves him open to the charge that he is trying to have it both ways. He says he's not interested in politics, but he stepped into the culture wars to help the President. He talks about the sin of pride, but basks in the spotlight. And his ambitions are so vast that they practically invite scorn--uniting liberal and conservative Protestants, fixing Africa, transforming the very nature of American culture. "We have a goal to move Christianity in America from self-centeredness to unselfishness," he says. Now, as this purpose-driven pastor steps onto the national stage, he faces new questions: What will he do with his influence? Can he turn evangelicalism in a new direction? Will success spoil Rick Warren?

The first time I saw Warren, he was striding down the aisle of a United Air Lines flight--the middle leg of a 24-hour journey from Los Angeles to Kigali, Rwanda--handing out Chick-fil-A sandwiches to church members on the trip. He stopped to help a stranger get her luggage into the overhead, glad-handed the flight attendants, patted people he knew on the shoulder, and went back to his seat in business class.

Like a politician who loves the campaign trail, Warren feeds off people. A large, gregarious man with spiky hair and a goatee, Warren dresses in Hawaiian shirts and wears no socks, even on stage at Saddleback. He's known as Rick or Pastor Rick, not Reverend Warren. "Rick is not sophisticated in any way," says his wife, Kay. "He's always been the class clown." He jokes about his weakness for doughnuts, and he uses one-liners to deflect questions he'd rather not answer. Ask about politics, and he'll reply, "I'm not left wing and I'm not right wing. I'm for the whole bird."

Rick and Kay, married 30 years, were both the children of small-town pastors. Rick's father, Jimmy Warren, was a "church planter" and carpenter; he literally built dozens of small churches. The family never had money, but Jimmy, like Rick, was a down-to-earth guy with a big personality. Rick first thought about going into politics but turned to the church in high school. He started Saddleback in his apartment in 1980.

In the quarter-century since, Warren has developed an approach to management that drives all his enterprises. He challenges people to think big. He is patient about results. And he builds decentralized organizations. "Most people make two common mistakes," Warren says. "We set our goals too low, and we try to accomplish them too quickly."

A student of business, Warren has read Drucker, Alvin Toffler, Ken Blanchard, Tom Peters, and Jim Collins. But he says he learned his most important lesson about leadership soon after starting Saddleback. As the church grew, Warren tried to do everything himself--preaching, weddings, funerals, pastoral counseling, and seeking out new members. He collapsed during a Sunday service and endured a period of depression and doubt. "If you're going to have a midlife crisis," he says, "it's nice to have it when you're 26." He came away with an insight that eludes micromanagers everywhere--that for an enterprise to grow, the leader needs to give up control.

"In any organization, you have to decide whether you want growth or control," Warren says. "You cannot have both." Warren told his flock that he could no longer take care of them and that, from then on, they'd have to care for one another. They would do that by forming small groups.

He had hit upon an organizational structure that has allowed Saddleback to get big and stay small. Today it has 3,300 small groups organized by neighborhood, interests, or experiences: men, women, teens, mothers of preschoolers, people who speak Korean, wives of unbelievers, fitness buffs. ("How can you serve the Lord to the fullest if your body is rundown, tired, and not functioning as God designed it to function?" says an ad for an aerobics group.) Saddleback says it was the first church to go on the Internet, and a key function of its website today is to organize the groups, which typically meet weekly to pray, study the Bible, and do good works.

"Rick's powerful, but there's nothing more powerful than a group of seven or eight people who support one another and care for one another," says Brian Conner, an architect and former Toyota executive who has belonged to Saddleback since 1992.

By his own account, Warren is uninterested in operations. He is neither well- organized nor disciplined. "I'm a startup guy," he says. "I'm not a maintenance guy." A core team of about a dozen pastors and lay people manages the church and the Purpose-Driven nonprofit, as well as Warren's extensive travel and speaking schedule. A colleague explains, "Rick is like a hurricane. Before he blows into a place, some of us are the weather service, preparing for his arrival. Others come in after to clean up."

His Purpose-Driven Ministries nonprofit began when other pastors asked to visit Saddleback, hoping to learn why the church had done so well. To manage his time, Warren organized brown-bag lunches and church tours. They morphed into conferences about church-building that draw 3,000 or 4,000 ministers at a time. In 1995 Warren wrote a manual for building healthy churches called "The Purpose-Driven Church" that sold more than a million units. He sold books and tapes by mail, and by the time the pastors.com website launched in 2000, he had a big following.

Signs of Warren's influence can be found in many corners of America. This month 15 churches in Lodi, Calif., are organizing a campaign called "40 Days of Community" that includes service projects and lessons in spiritual growth using Warren's teachings. In Midtown Manhattan, a four-year-old evangelical church called the Journey regularly attracts 1,000 people. Started by a former Saddleback minister, it bills itself as a "casual, contemporary Christian church" and uses rock music and movie clips to teach biblical principles. Last year Mel Gibson persuaded Warren to use his network to spread the word about The Passion of the Christ, his movie about the death of Jesus that stunned Hollywood by grossing $370 million in the U.S. "All of it depends on the network," Warren says. "If I want to rally people, I push a button, and boom!"

Warren posts his sermons on the Internet, and sends a weekly e-mail to pastors with tips on church-building such as "10 Ways to Worship Without Music." He has a special fondness for small-town pastors like his dad. He says, "That guy's out flipping burgers or working as a mechanic during the week, and then, in four hours, trying to come up with something to say on Sunday.... If I can help that guy, if I can move him from a C to a B preacher, so be it. I'll make him a hero."

When Warren led a delegation of about 50 Saddleback members and other supporters to Rwanda in July, he was treated like visiting royalty. He dined at the ranch of President Paul Kagame, met with business leaders, and borrowed the President's helicopter to tour church projects. Visiting a town near Rwanda's famed gorilla reserve, Warren was met by a dance troupe and a band of drummers--a welcome that most dignitaries would have acknowledged with a smile or a wave. Not Warren. He joined the dancers, his shirt flapping in the wind, then grabbed a pair of drumsticks and whacked away until the local Anglican bishop pulled him away to a briefing.

This man is going to defeat poverty, illiteracy, and disease in Africa? The notion that anyone, let alone a white, middle-class minister from Orange County, can parachute in and figure out how to address problems that for decades have resisted the efforts of Western governments, aid groups, and Africans themselves--well, it brings the word "hubris" to mind. Selling books is one thing, stopping malaria quite another.

Warren is a latecomer to the cause of social justice, as he confessed to about 500 church leaders in a hotel in Kigali, the Rwandan capital. "I have been so busy building my church that I have not cared about the poor," Warren said. "I have sinned, and I am sorry." He says much the same thing about AIDS. "I felt like anyone who was HIV-positive probably deserved to be ill," he said.

It was Kay who changed his mind, after she read a magazine story that said Africa was home to 12 million orphans. The number haunted her. She consulted with experts and then visited Mozambique. "AIDS became personal," she says. Soon AIDS became Rick's cause too.

PEACE stands for Partner with or Plant churches, Equip servant leaders, Assist the poor, Care for the sick, and Educate the next generation. "We don't know how to do this," he told the pastors in Kigali, "but together we can figure it out. I'm going to get the best minds I can to help me." About all he knows for sure is that the project will be driven by local pastors who will get help from churches in the developed world. "The church has a distribution point in every community," he says, "and we have a massive army of volunteers that neither business nor government has." On the contentious issue of whether to support the distribution of condoms to help prevent AIDS, Warren has yet to take a public stance. He told FORTUNE he was studying the question, but an aide says he will likely adopt the successful ABC public awareness campaign in Uganda; that stands for abstinence, be faithful, and when all else fails, use condoms.

Some businesspeople have bought into the PEACE plan. Murdoch gave $2 million. Saddleback members like John Kang, a tech-industry CEO, are lending expertise. So is Ritchie, the former Chicago options trader; he is so impressed with the quality of Rwanda's leadership, particularly Kagame, that he has recruited other CEOs to help stimulate entrepreneurial efforts there.

Warren would like to make Rwanda the world's first "purpose-driven nation." The tiny, mountainous land, which suffered a genocide in 1994, is quietly regenerating itself. Speaking to a rally in Kigali, Warren said, "In the Old Testament, God took a small nation and He blessed the world with it.... Just as God used Israel to bring the Good News to the world, I believe that God wants to use Rwanda, this nation, in the 21st century."

Skeptics abound. An International Monetary Fund study released in June found that $1 trillion in foreign assistance had been spent in Africa in the past 50 years without much to show for it. "I do not believe that Rick Warren has a bad bone in his body," Alan Wolfe, director of the Boisi Center for Religion and American Public Life at Boston College, has written. "But I do believe that his remarkable enthusiasm is fueled by considerable naiveté."

Touring Rwanda on the presidential helicopter. Chatting with George Bush in the White House. Receiving a standing ovation at Harvard. Whose head wouldn't swell?

Success has created unexpected problems for Warren. He has to manage his ego (not easy) and his wealth (easier, because he's giving 90% of his income away--riches have clearly not spoiled this guy). But he has come under intense scrutiny. Toughest of all is the political task he has taken on: He wants to get a broad swath of Americans to use churches to fight poverty at a time when the nation is divided along religious lines by issues like abortion and gay rights.

Warren is grappling with a question familiar to anyone with political ambitions: Once you have made a name for yourself by appealing to a core constituency, how do you broaden your appeal without alienating your base? He wants to win over two radically different constituencies. Many evangelicals, despite their political clout, see themselves as an embattled minority, under siege from liberal judges who want to drive religion out of the public square and a Hollywood culture that promotes extramarital sex and gay rights. Secular opinion makers, meanwhile, fear that conservative Christians want to impose their values on everyone else by, for example, banning the use of embryonic stem cells in research or forcing public schools to teach "intelligent design."

"There is a great deal of anxiety, whether it's among secularists or Jews or Roman Catholics or evangelicals, about whether their values will be respected and whether they will ultimately prevail," says John C. Green, a senior fellow with the Pew Forum on Religion and Public Life. "Everyone feels beleaguered and persecuted. And with some justification."

Warren has attracted flak from traditionalist evangelicals, who accuse him of winning followers by toning down what they say is the core message of the Bible about hell, sin, and the wrath of God. Two books attacking his ideas have been published by Christian presses. "He has been called a wolf in sheep's clothing, a liar, deceiver, a poison dispenser, a follower of a false god, a compromiser, an occultist, a huckster, and a money-grubbing preacher," says Richard Abanes, a former staff member at Saddleback who has written his own book, a defense of Warren.

This is so even though Warren is entirely orthodox when it comes to the culture wars: Like other evangelicals, he opposes abortion, gay marriage, stem-cell research, human cloning, and euthanasia. What's more, on the eve of last year's Presidential election, he wrote that those five moral issues are "nonnegotiable" and "not even debatable." Leaving no doubt about his political leanings--Bush allied himself with evangelicals on all those issues--Warren urged pastors to "encourage every Christian you know to vote" and "pray for godly leaders to be elected." Today, Warren says the letter was an anomaly. "I've never done that in any previous election," he says. But he doesn't disavow the message.

What Warren would really like to do is change the subject. Before secular audiences, Warren distances himself from the rancor of conservative Christians like Pat Robertson and Jerry Falwell, who condemn gays, feminists, activist judges, Venezuelan dictators, and most politicians to the left of Tom DeLay. "Rick is not mad at anyone," says Michael Cromartie, a fellow at the conservative Washington-based Ethics and Public Policy Center. By putting the issues of poverty and social justice atop his agenda, Warren would like to cross religious and political fissures. "I'm a bridge builder, not a divider," he says. Last summer, working with Bono and his antipoverty group, DATA, Warren called upon his network of pastors to urge President Bush to spend more on foreign aid, cancel the debt owed by poor nations, and lower trade barriers that hurt farmers in the global south. What he's aiming for, says Geoff Tunnicliffe, CEO of the World Evangelical Alliance, is a "rebranding of American evangelism."

That's what concerns people like Wendy Kaminer, a liberal author who has written about Warren. Rebranding won't change the fact that he is part of a large, influential conservative movement that threatens the rights of others. "From my perspective," she says, "seeing them gain power is not a good thing."

Take the issue of gay rights. On the one hand, Warren says he and Kay have had dinner with gay couples who are their allies in the fight against AIDS. "I'm no homophobic guy," he says. "I have a church full of people who are caring for gays who are dying of AIDS." But he also says that he would counsel gays and lesbians to adopt a heterosexual lifestyle. "In looking at the hierarchy of evil, I would say homosexuality is not the worst sin," he says. "I just believe it's not the natural way. Certain body parts are meant to fit together. And that's all I have to say about it."

The hell question is another one that comes up when Warren speaks to diverse audiences. Because he does not want to sound harsh, Warren says things like "people who don't accept what Jesus said will end up where Jesus said they'd go." Lynda Resnick, a Los Angeles business executive and philanthropist who got into a debate with Warren in Aspen, came away liking him despite the hell problem. Besides, she says: "I suspect there'll be more people going where I'm going than where he's going. We'll be doing the hora, eating Chinese food, and wearing Indian saris."

Warren understands that religious differences can't be easily bridged. The world's religions "totally contradict each other" and are "mutually exclusive," he says. He wants to avoid doctrinal debates and play down the culture wars to do something about poverty and spiritual emptiness in Africa--and, of course, to get more people to accept Jesus Christ as their savior and the Bible as the literal truth. The church remains his No. 1 cause. As with so many things that touch on religion, what you make of Warren and his crusades may depend on where you stand.

Drucker, Warren's mentor, wrote in 1998 that the rise of megachurches like Saddleback was the most significant social phenomenon of the past 30 years, comparable to the rise of the corporation in the first half of the century. Judging from the political and social debates of the moment, he may have been right. Now that Rick Warren has entered those debates, he may or may not be able to resolve the contradictions that his role carries with it. But there is no doubt that he has shown himself to be his generation's great religious entrepreneur.

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