Editor's Note: Stephen Prothero, a Boston University religion scholar and author of "The American Bible: How Our Words Unite, Divide, and Define a Nation," is a regular CNN Belief Blog contributor.

By Stephen Prothero, Special to CNN

(CNN)–Why are evangelicals like Billy Graham and Ralph Reed stumping for Mitt Romney? And why are roughly three-quarters of white evangelicals inclined to vote for him?

Because politics matters more to them than religion.

Last year, in a talk at a conference on Mormonism and Islam at Utah Valley University, I asked my Mormon listeners why they had not rushed to the defense of Muslims in controversies such as the one that raged over the Park51 project near ground zero. After all, they have been the victims of religious prejudice. Their founder, Joseph Smith, was killed by a mob of vigilantes.

Given this history, I expected that members of the Church of Jesus Christ of Latter-day Saints, known as Mormons, would feel the sting of anti-Muslim prejudice and speak out against it. But neither Mitt Romney of the GOP nor Senate Majority Leader Harry Reid of the Democratic Party did anything of the sort. In fact, Romney issued a statement opposing the construction of the Islamic center.

Why? Because they were thinking and acting as Republicans or Democrats first and Mormons second.

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I see a parallel story playing out this election season with the religious right.

Until quite recently, many evangelicals saw Mormonism as a dangerous cult spreading false theology and dooming its followers to hell. In fact, only after Romney showed up for a meet and greet with Billy Graham in North Carolina earlier this month did the website of the Billy Graham Evangelistic Association erase a reference to Mormonism as a “cult."

Did Mormons all of a sudden change their theology? Did Graham change his definition of a “cult”? Of course not. It just became politically expedient for Graham to declassify Mormonism, given the fact that Romney, a Mormon, was the presidential nominee of his beloved GOP.

Ralph Reed, too, is forsaking his theology for his politics, mobilizing his Atlanta-based Faith and Freedom Coalition to place voter guides in Ohio churches in the run-up to election day.

I am old enough to remember when the main purpose of Reed’s Christian Coalition and other groups on the religious right was to put born-again Christians in the Congress, the White House, and the Supreme Court. And for decades those who were running those groups saw Mormons as non-Christians.

And don't get me started on Mike Huckabee, who in a recent ad says that a vote for Obama is a vote for your own damnation.

Have LDS Church members repudiated the Book of Mormon as “another testament of Jesus Christ” or their view that the Bible is the word of God only “as far as it is correctly translated”? Have they accepted the Trinity? Rejected their teaching that there are many gods?

As Ben Witherington, Albert Mohler, and many other evangelical thinkers continue to insist: no, no, and no.

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I used to believe that the purpose of the religious right was to infuse American politics with Christian politicians and Christian politics. I no longer believe that. The purpose of the religious right is to use the Christian God for political purposes. Why any Christian, conservative or liberal, can say "Amen" to that is beyond me.

I am perfectly happy to see Reed stump for Romney in Ohio and Graham plump for Romney in an ad in The Wall Street Journal. Just don’t tell me they are doing so as Christians. They are doing so as shills for the GOP.

The opinions expressed in this commentary are solely those of Stephen Prothero.