Presidential elections often serve as measuring sticks for change in our country. If that trend holds this year, then conservative Christianity likely has passed its zenith in power and influence.

With John McCain headed for the Republican nomination, and Hillary Clinton and Barack Obama fighting it out for the Democratic nod, many conservatives feel left out.

Conservative Christianity's decline in influence mirrors the fate of the mainline church in the mid-1960s. In the late '50s and early '60s, Episcopalians, Lutherans, Methodists, Presbyterians and other mainline Christians dominated public discourse in America. They helped elect presidents and congressional leaders. But after 1964, their power and influence sharply declined.

The reasons for this decline were many, including missteps in the mainline church's approach. But it also reflected a time of social upheaval that left many in society yearning for a clear, black-and-white faith - in other words, conservative Christianity.

Now the growth of these conservative churches is likely to stall, then decline, unless they recognize the changes happening in society, which will leave them increasingly disconnected from emerging generations.

One of the most obvious signs of this is the change in political fortunes for conservatives, but I see it anecdotally in many other places as well. At one of the leading conservative seminaries in the United States, students question the doctrine of inerrancy (while the school continues to officially embrace it). I hear it from my friends who pastor large Southern Baptist churches as they express their frustration over the infighting that has racked their denomination in recent years.

I sense it in the passion of a young pastor who leads a relatively new nondenominational church. He recently led his congregation to carry signs in a crowded shopping area in Kansas City announcing that "God loves gay people." And, on this issue, I hear it when speaking with my teenage daughter's friends who attend more conservative churches, yet who reject their parents' views on homosexuality.

I see it in the evangelical publishing giant Zondervan Press' publication of an inclusive-language edition of the New International Version of the Bible, despite the protests and boycotts of the old guard among conservatives in America.

I hear it in the willingness of an increasing number of traditionally conservative churches to embrace women in leadership positions in the church, including female pastors.

I see it in the evangelicals who are speaking out against global warming even though some leading conservatives dismiss it as a hoax. I hear it in the questions raised by some very thoughtful writers in the evangelical magazine Christianity Today concerning war, poverty and AIDS.

And I've seen it in the ministries of two of the leading evangelical megachurches in America: Willow Creek Community Church in South Barrington, Ill., led by Pastor Bill Hybels; and Saddleback Church in Lake Forest, Calif., led by Rick Warren. Both men have moved from a ministry focused almost exclusively on evangelism to one that recognizes the call of Christ to care for those in need. These men, and the churches they have influenced, are beginning to resemble the best of the mainline tradition.

There will always be Christians on the right and on the left, but an increasing number of Christians are drawn to the center, increasingly able to see the gray in a world of black and white.

All you have to do is look at the presidential race to see that.