Perhaps the most significant recent event in the 2008 presidential contest took place in the massive church in Lake Forest, Calif. That’s where Senator Brownback of Kansas and Senator Obama of Illinois made the pilgrimage to address the attendees at the Reverend Rick Warren’s Saddleback Church for the World AIDS Day Summit.

The event marked an important opportunity for these two would-be presidential candidates to attempt to fill a niche that is as of yet unfilled in the campaign — the anointed candidate of religious Christians. With all the attention that the Republican wipeout in November has garnered, a looming problem in the 2008 election cycle has yet to be resolved. While the Iowa caucuses are a mere 13 months away, there is still no consensus candidate for religious conservatives.

Each of the three candidates often cited as having front-runner status for the conservative vote, Senator McCain, Mayor Giuliani, and Governor Romney, has a unique problem that could prevent him from garnering unified support in the evangelical community, typically an important building block in winning the Republican nomination.

When Mr. McCain ran for the nomination in 2000, he attacked religious conservatives, such as the Reverend Jerry Falwell. He has subsequently attempted to bridge his differences with Mr. Falwell and spoke at the religious leader’s Liberty University in the spring of 2006.

Mayor Giuliani, a strong leader and stalwart supporter of the war on terror, is also a moderate on social issues, such as gay rights and abortion. This makes him something less than a natural fit for religious conservatives.

Governor Romney has thrust himself into the national limelight as an opponent of gay marriage. His road of religious conservatism through the Church of Jesus Christ of Latterday Saints represents a different path from most religious conservatives in America, who are evangelical or Baptist.

Molly Worthen, a Yale University scholar of religion, recounted in the New Republic her encounter with several evangelical Christians who tried to challenge the religious beliefs of Mormons at an annual Mormon pageant in Palmyra, N.Y. Of these evangelicals, Ms. Worthen writes, “although they seem like the lunatic fringe, [they] represent an entrenched anti-Mormon movement that is prepared to convince voters that Romney’s religion renders his campaign promises and political record moot.”

Mr. Romney has gone a long way to allay many of these concerns, at least with established religious leaders. Last month he met with Mr. Falwell and the Reverend Franklin Graham along with Gary Bauer, a former Republican presidential candidate and the head of American Values. After the meeting, Mr. Falwell told the Associated Press “where he goes to church will not be a factor; how he lives his life will be.”

Mr. Bauer says he can’t predict what impact Mr. Romney’s Mormon faith will have on his appeal to an evangelical electorate. “What I’m going to look at are issues and not where somebody worships,” he adds, noting he has not endorsed Mr. Romney.

During the 2000 election cycle, Marvin Olasky, a University of Texas professor and an adviser to then Governor Bush, helped spark a mini-firestorm when he likened supporters of Mr. McCain to “proselytes in the religion of Zeus.” Mr. Olasky subsequently emphasized that his awkward reference came from Tom Wolfe’s novel “A Man in Full,” where an imprisoned character prays to Zeus.

Nowadays, Mr. Olasky is the editor in chief of World Magazine, a Christian-oriented weekly publication. Asked in e-mail about the current Republican field, he had this to say: “It’s still early. I wrote a book in the late 90s, ‘The American Leadership Tradition’ which among other things looks at trustworthiness in marriage as a leading indicator of trustworthiness in public office, so I’d like to know a lot more about several of the candidates. Regarding Giuliani, I’d like some sense of the types of judges he would be likely to appoint. McCain and Giuliani have name recognition right now, but January surprises are now traditional in election years.” While unwilling to officially endorse any one candidate, Mr. Olasky did trumpet one dark horse candidate — Senator Brownback. “Brownback is embracing compassionate conservatism, and that could have great appeal to religious conservatives.”

For Mr. Brownback, his path to the White House will hinge heavily upon whether he can perform well in Iowa, a rural, agricultural-heavy state like his own. But Mr. Brownback does not have to win the caucuses to cause trouble for the Republican front-runners. All he must do is bleed support from the others.

When Republicans do not win heavy support from religious conservatives in general elections, they lose. High and enthusiastic support, in turn, can insulate a GOP candidate. In 2004, Karl Rove built his GOP turnout machine on religious conservatives. That decision enabled Republicans to win northern Nevada by a 9-1 margin and capture the important swing state. Of note for Mr. Romney, the area of northern Nevada includes both evangelical Christians and Mormons.

Division and demoralization among religious conservatives is a boon to those Democrats who are smart and skilled enough to exploit those factors. In 1992, Bill Clinton ran for president as a small-town Southern Baptist from a Southern state against a culturally Northeastern Episcopalian. Mr. Bush won 55% of the votes of Christian conservatives — this represented a downturn from prior elections.

Press accounts suggest Mr. Obama drew a warm reception last week at Mr. Warren’s church. An advocate of Democrats reaching out more rigorously to religious voters, Mr. Obama, according to the Chicago Tribune, said “my Bible tells me that when God sent his only Son to Earth, it was to heal the sick and confront the weary.”

Such language suggests that we will hear more about God from Democrats in the coming months. Perhaps we will learn more about Senator Clinton’s status as a member of the Methodist Church, the same faith adhered to by none other than President Bush.

Mr. Gitell (gitell.com) is a contributing editor of The New York Sun.