Scenes from two evangelical Christian congregations: In the first church, members sit quietly in their pews and follow along intently as the minister preaches a long sermon based on a biblical text. As they pray, they ask God to cleanse them of their sins.

In the second church, members sing and sway to Christian pop music, clap and "amen" as an evangelist preaches about getting right with God. They lapse into a mysterious, ecstatic language, surge forward to the altar to be prayed over, and fall backward, "slain in the spirit," as they are overcome with joy.

The first church is fundamentalist; the second is Pentecostalist. Politically speaking, the first church is affiliated with people and groups like Jerry Falwell, Bob Jones University, and the Christian Coalition. The most prominent politician from the Pentecostal movement: John Ashcroft.

In a sense, the fate of the religious right--and the Bush presidency--may be determined by this question: Will John Ashcroft be guided more by the spirit of Pentecostalism or fundamentalism? This may seem like an arcane theological debate, but it relates to bread-and-butter issues like gay rights and poverty and, more specifically, to whether George W. Bush's notion of "compassionate conservatism" will be seen as an empty slogan or a defining theme of his administration.

The confirmation of Ashcroft as attorney general clearly proves that conservative Christianity has gained the acceptance that members long craved. Falwell demanded that acceptance when he started the Moral Majority in the 1970s; Pat Robertson, who is a Pentecostalist, gained a little more when he ran for president in 1988 and then formed the Christian Coalition. But neither of them was ever elected to office. Now, after all these years, religious right leaders have managed to push their views--anti-abortion, anti-gay rights, pro-traditional family, anti-public schools, anti-evolution--to the center of the political arena. By contrast, when Ronald Reagan appointed a fundamentalist, James Watt, to the Cabinet, it was as Secretary of the Interior--not exactly ground zero for the culture wars.

This is a critical time for evangelical Christianity. Americans continue to migrate to the South and West, where conservative Christianity is strongest. There, they encounter country music, evangelical megachurches, stay-at-home mothers' groups, men's prayer breakfasts, gospel music in fast-food restaurants, Bible shops at the local mall, and a folksy lingo ("I feel blessed" and "It's on my heart").

But while Americans have grown more comfortable with the evangelical subculture, many remain queasy about the thou-shalt-not emphasis of modern fundamentalism. Surveys show that American Christians don't like legalisms in their Sunday sermons. They want bite-size nuggets of wisdom for daily living, souped up with spirit-filled, rocking worship.

"A very visible trend in the last couple decades-and not just in Christianity-is movement away from a more institutional and doctrinal definition of religion to a more experiential religion," says Harvey Cox, a Harvard Divinity School professor and the leading authority on Pentecostalism.

And that is why Pentecostalism is such a draw. All over the country, unchurched secularists, disgruntled former Baptists and Catholics, inner-city and suburban African-Americans, and Hispanic Catholics are joining Pentecostal churches. Globally, Pentecostalism is spreading rapidly in the Third World, even usurping the Catholic Church's longstanding spiritual leadership in Latin America. In this country, a sort of "Pentecostalism lite" is spreading in many churches, featuring healing services and a looser music style. Born as a multicultural movement, Pentecostalism remains so to this day. And Pentecostals have always ordained women as evangelists and ministers.

Many fundamentalist followers of Falwell or Bob Jones University actively distrust Pentecostalists because they believe the practices of healing and speaking in tongues de-emphasize the authority of scripture. Baptists have been known to "disfellowship" any congregation that displays Pentecostal leanings.

The gulf between the two groups goes beyond theology. Pentecostals' emphasis on the "gifts of the spirit"--speaking in tongues, healing, and prophecy--leads them to a softer politics. Although they agreed on nearly every issue with former presidential candidate Gary Bauer, for instance, most Pentecostals were turned off by him because they thought he sounded too harsh.

At a typical revival service--whether it's at a megachurch in the suburbs or a storefront church in the ghetto--an evangelist ends with an altar call, asking "sinners" and "backslid Christians" to come forward and profess their faith in Jesus. And they always stream forward, often weeping. Pentecostalists are famous for bringing some of the sorriest elements of society--gang members, criminals, prostitutes--into their fold, and keeping them straight.

This means they tend to be forgiving. For instance, although they believe abortion is a sin, they will also go out of their way to shower a woman who has had an abortion with love and a second chance.