When Episcopal Bishop Gene Robinson of New Hampshire heard about President-elect Barack Obama's choice of Rick Warren to present the invocation at his inauguration, Robinson felt as if he'd been slapped in the face, he recently told the New York Times.

Little wonder. Robinson is his church's first openly gay bishop and was an early and outspoken supporter of Obama's presidential bid. Warren, pastor of a California mega-church and author of the popular self-help book, The Purpose Driven Life, has compared gay relationships like Robinson's to incest, polygamy and "an older guy marrying a child."

To Obama, giving Warren a high-profile role at his inauguration is a step toward building bridges across the political and cultural divides that sometimes feel like chasms in America. To Robinson and thousands of other gay Americans, Warren's participation looks like an endorsement of the very bigotry they are fighting.

"The God that he's praying to is not the God that I know," Robinson said of Warren.

Of course, Robinson's version of God doesn't square with the beliefs of some in his own church, as evidenced by the brouhaha his 2003 consecration continues to cause among conservative Episcopalians and Anglicans in the United States and around the world.

Which makes you wonder: How could any president-elect find a minister to offer a religious prayer that would simultaneously be truly meaningful and truly satisfy everyone?

More important: Do we need an inaugural prayer? Somehow, in a country that has become more and more diverse, a country that includes not only Protestants, but also Catholics, Jews, Muslims, Hindus, Buddhists and nonbelievers, the tradition seems an anachronism that future presidents would do well to scrap.

Formal prayers by Christian ministers have been associated with presidential inaugurations from the get-go, but they're surely no requirement. And while you might assume such prayers would be of the tepid, generic, non-denominational variety, a quick look back at recent overtly religious invocations will surely give many Americans, regardless of their personal religious affiliations, pause.

Consider:

• During George W. Bush's first inauguration, the Rev. Franklin Graham prayed, "May this be the beginning of a new dawn for America as we humble ourselves before you and acknowledge you alone as our Lord, our Savior and our Redeemer. We pray this in the name of the Father, and of the Son, the Lord Jesus Christ, and of the Holy Spirit."

• During Bill Clinton's and George H.W. Bush's inaugurations, prayers were offered "in the name of the Father, the Son and the Holy Spirit."

• At Jimmy Carter's inauguration, the prayer urged Americans to "build a nation here on earth that in its manner of life anticipates Thine everlasting kingdom in heaven . . . in the name of Jesus Christ, Thy Son and our Savior."

Such language is meaningful and powerful to Christians - but foreign and exclusionary to other Americans. Does it belong in a civil ceremony marking one of the most cherished rituals of American democracy, the peaceful transfer of power from one chief executive to the next?

A presidential inauguration is the perfect time to celebrate American democracy, for speakers to encourage government leaders to reaffirm their belief in the Constitution, to challenge them to resolve differences peacefully, to imagine a government that looks out for the least of us and treats all citizens with justice and compassion. It is a day to remember what unites us as Americans. As the flap over Rick Warren has shown, specific religious belief is not one of those things.