Question: Why are so many news stories on religion in America about sex, politics, and litigation? Answer: Religion in America is grappling, as seldom before, with hot-button issues that congregate under the broad topics of sex, politics, and litigation. Whether it’s the sexual abuse of teenagers by Roman Catholic priests, or the ordination of active homosexuals in the Episcopal Church, or the burgeoning influence of evangelicals in national politics, or where the line ought to go that separates church and state, religion is in the crosshairs of a larger cultural conversation that occasionally turns into a fight.

You can certainly argue that the press has wallowed, sometimes in unseemly fashion, in the most sensational aspects of these matters. But the facts speak for themselves: These are the topics the churches are addressing. What is sometimes neglected in all this are the actual trends shaping the future of what is loosely referred to as organized religion in a nation that remains – uniquely among the wealthiest democracies – remarkably devout and religiously diverse.

Larry Witham, an award-winning religion writer, has done yeoman service in providing a measured and even-handed survey of the people who are and will be occupying the nation’s pulpits. “Who Shall Lead Them” (Oxford University Press, 246 pages, $26) focuses heavily on numbers and polling data, but the author conducted numerous interviews and the personal stories that emerge are both telling and entertaining.

The book has limitations. As Mr. Witham cheerfully concedes, he has little to say about the Christian Orthodox, the Mormons, and a number of other, smaller organizations. He has some interesting observations about the American Rabbinate, including their comparatively higher income, education, and status within their communities. But I would have liked to see a bit more comparative data on Orthodox, Conservative, and Reform Judaism.

In the end, the volume sheds its most interesting light on the struggles and trends within Main Line and Evangelical Protestantism and, to a lesser extent, the epic battle shaping up over governance and practice in the nation’s Roman Catholic churches.

Much has been written over the years about the long decline of the Main Line Protestant churches, and Mr. Witham provides no data to suggest a revival. He does have some very useful reporting and commentary on the pivotal struggle for women’s ordination in the Main Line. While he takes no side in the dispute, he identifies a link between women’s ordination and the far more rancorous debate over non-celibate homosexuals.

Studies suggest, for instance, that women in ministry are more likely than their male counterparts to support ordination for active homosexuals, and pro-ordination forces frequently cite earlier opposition to the ordination of women to justify their arguments for ordaining homosexuals. Mr. Witham also points out the underreported trend of “pioneer” women leaving ministry because they have hit a “glass ceiling.” Women lead smaller and poorer congregations, while the most desirable positions go mostly to men.

Here, as elsewhere, Mr. Witham traces the cultural divide between pulpit and pew. When the congregation has a say on who is hired, the ideal and desired candidate is usually a married man. This divide is most evident in the debate over homosexuality, with the pews pretty consistently more cautious than the pulpits.

The author hits his stride when he turns to the rapidly growing and increasingly influential Evangelical churches. He traces the history of the Southern Baptists in a discrete chapter and describes how conservatives recaptured the leadership of this denomination, now the largest segment of Christianity other than Roman Catholicism, through a series of fiercely fought elections dating to the 1970s.

That the conservatives ever needed to recapture power among Southern Baptists may come as a surprise to the uninitiated reader, but it is a powerful indication of the distance between pulpit and pew in many Protestant churches. Readers who are interested in the rise of conservative politics in Christian churches that were once either apolitical or downright hostile to political activism will find much of interest in Mr. Witham’s dispassionate account. Even more interesting is his reporting on the “mega-churches” that have increasing sway in the exurban stretches of states like Florida and Ohio, and where turnout in the 2004 election may have been critical to President Bush’s re-election.

Also critical to the re-election of the president was the Catholic vote, which rejected the first Catholic presidential candidate since John F. Kennedy by a respectable margin. Mr. Witham is on less certain ground here and for good reason. It’s doubtful anyone has a reliable divining rod for the multiple conflicting currents shaping what is the nation’s largest denomination by far.

Unlike Protestants, Catholics tell pollsters that they are much more liberal than their leaders on a range of issues from women’s ordination to abortion. The problem with most of those polls, however, is that they fail to discriminate between self-identified Catholics and Catholics who regularly go to Mass. While attendance is higher on average than for many other denominations, it has been falling.

This, combined with the abuse scandal, the election of a new pope, and a growing role for the laity, has made it hard to predict how this church will operate in years to come. Mr. Witham does provide useful information on priestly attitudes: the younger the priest the more conservative he is on faith and morals. And while he makes no excuses for the monsters – most of them older or elderly – who had sex with minors, he emphatically restates what everybody knows: Anti-Catholicism is “the last acceptable prejudice,” regularly indulged in by many people who should know better.

This is a perceptive and informative book on a part of the culture that is enormously consequential for believers and nonbelievers alike.

Mr. Willcox last wrote in these pages on Josef Stalin.