In "The Protestant Establishment," E. Digby Baltzell chronicled the "growth and decay" of the WASP aristocracy, describing its patrician families, elite boarding schools and Ivy League universities and noting their waning influence. Writing in 1964, Baltzell saw the election of John F. Kennedy, an Irish Catholic, as a hopeful sign. And, indeed, later researchers documented the opening of the elite to Catholics and Jews.

Missing from most accounts of America's diversifying establishment is any discussion of what happened to the other Protestants--the fundamentalists and evangelicals outside the mainline. A few attained positions of power in midcentury America, but for decades most could be found near the bottom of the economic ladder in the South and Midwest. The victims of class and regional prejudices, these born-again believers had been christened the "gaping primates from the upland valleys" by H.L. Mencken. He wasn't alone is taking such a view.

Yet a funny thing happened on the way to the 21st century. Buoyed by the upward mobility of postwar America, a critical mass of evangelicals made it into the elite. In "Faith in the Halls of Power," D. Michael Lindsay tells their story, drawing on interviews with 360 prominent evangelicals to gauge the rise of a conservative Protestant leadership class in government, business, the media and higher education. Among the voices to be heard in Mr. Lindsay's fascinating book are those of two former presidents, 100 corporate executives, two-dozen cabinet secretaries and White House officials, and a dozen Hollywood filmmakers and actors.

Who would have guessed that a president of Borders, a Juilliard School dean, the producer of "The X-Men" trilogy, the world-wide head of television for the William Morris Agency, a host of TV's "Talk Soup" (now called "The Soup") and a former director of marketing at Tommy Hilfiger were all evangelicals? At a Manhattan gathering in honor of the evangelical author Rick Warren, Mr. Lindsay overheard an editor at a major publishing house ask: "Are there many evangelicals at Yale these days?" The short answer is yes. An update of William F. Buckley's "God and Man at Yale" (1951) would have to acknowledge Yale's dramatic growth of evangelical student groups. The same goes for Harvard, where chaplain Peter Gomes notes there are more evangelicals "than at any time since the seventeenth century."

How did evangelicals join the elite? Like their WASP predecessors, they put together "dense, overlapping social networks," Mr. Lindsay says. In Washington, they created Bible-study and prayer groups, bringing a sense of religious cohesion to offices on Capitol Hill and even in the White House. In the worlds of entertainment and the arts, they launched dozens of organizations, like the International Arts Movement and Act One, a program that (according to its Web site) "trains and mentors Christians of all denominations for careers in mainstream film and television." In higher education, they founded scholarly associations and mentoring programs aimed at both Christian colleges and the Ivy League. Underwriting all of this was a cadre of philanthropists, including the Pew Charitable Trusts and the Fieldstead Foundation.

More than a few writers and pundits, noting the new prominence of evangelicals in American life (not least, that of George W. Bush), warn of a looming theocracy with proselytizing impulses and apocalyptic visions. But Mr. Lindsay, listening to his interview subjects talk about their faith, "found little support for the conspiracy theorists who think evangelicals are plotting to take over America." For starters, the members of the evangelical elite are too divided to embrace a single ideology. Most are Republicans, but many others lean to the left. The first politician profiled in "Faith in the Halls of Power" is Jimmy Carter. Al Gore, Mr. Lindsay notes, participated in Washington's evangelical prayer groups, too.

Many evangelicals in high positions, in fact, reject the "populist evangelicalism" of the new Christian right. They go "out of their way," Mr. Lindsay observes, to say that they have "never read Left Behind," the series of end-of-the-world novels by Tim LaHaye and Jerry Jenkins. Instead of celebrating "apocalyptic pot-boilers," one-fourth of Mr. Lindsay's interview subjects cited C.S. Lewis as a strong personal influence. Pat Robertson's Regent University and the conservative Patrick Henry College have produced some influential graduates, but many of the people in Mr. Lindsay's survey have gone to schools like Harvard and the moderately evangelical Wheaton College.

If the rise of what Mr. Lindsay calls "cosmopolitan evangelicalism" threatens anything, it may be the internal coherence of the evangelical movement--its down-home traditions and sense of itself as a religious identity for ordinary Americans. In short, some evangelicals may be "getting above their raising." Though some Christian CEOs (like Ralph Larsen of Johnson & Johnson) give away so much of their money that their colleagues find it "goofy," most "accept the material accoutrements of an affluent lifestyle," Mr. Lindsay notes. The evangelical elites he spoke to also look down their noses at the Christian kitsch of their fellow believers-- like the paintings of Thomas Kinkade, whose scenes of cozy lamplit cottages hang in a lot of heartland homes.

Mr. Lindsay hints at the ethical implications of evangelicalism's growing class divide, but he might have said more. As one of his respondents noted elsewhere: "The main goal in life is not to gain power but to undertake a journey guided by the ideals of the gospel." Something for the evangelical power elite to ponder.

---Mr. Schmalzbauer, a professor of religious studies at Missouri State University, is the author of "People of Faith: Religious Conviction in American Journalism and Higher Education" (Cornell, 2003). You can buy "Faith in the Halls of Power" from the OpinionJournal bookstore.