"His marital history has been duly recorded," said the Rev. Kirbyjon Caldwell in a conference call with reporters. "And as recently as yesterday I think it is, our pastor from Saddleback, Rick Warren indicated that he would not feel comfortable voting for an adulterer and I don't know exactly to whom he was referring but I think the data speaks for itself... At the end of the day again I think the American public deserves full revelation of the candidate's character and competency."
Caldwell also laced into McCain for recently suggesting that his wife enter South Dakota's Buffalo Chips contest, which is a topless beauty pageant.
"My personal opinion and based on my understanding of the Christian faith, that's not not not, N-O-T the type of expression that a presidential candidate, or anyone for that matter who is a follower of the Christian faith ought to make," Caldwell said.
McCain spokesman Brian Rogers said today that the Arizona senator knew that it was a topless contest, but that he was joking and not actually volunteering his wife for it.
Caldwell is part of the Matthew 25 Network, a liberal Christian group, that is going to air a pro-Obama ad on Saturday during the Rick Warren forum.
McCain, who was raised Episcoplian, attending Episcopal High School in Virginia, now attends a Baptist church, and has always appeared ill-at-ease talking about religion.
But his campaign has begun to emphasize his faith.
In an interview with the Chicago Tribune, McCain recalled that while he was a POW during the Vietnam War, he was chosen to be the chaplain to his fellow prisoners and that he relied on his faith to survive.
"I think it's remarkable that I've been able to survive so much and to have the opportunity to do the right thing. I do think we make our own choices, but certainly I think I was meant to serve a cause greater than my self-interest," McCain told the paper.
The battle for the evangelical vote is the latest example of religion affecting the 2008 race for the White House.
Obama has had to deal with persistent rumors that he is Muslim, an accusation that he tried to parry early on with the quip, "This would surprise my pastor at Trinity United Church of Christ.
But Obama had to eventually leave the church because of the fiery sermons by his pastor, the Rev. Jeremiah Wright, who was quoted in the wake of 9/11 saying the United States had provoked the attack and railed, "Goddamn America."
McCain was forced to reject the endorsement of two ministers.
The Rev. Rod Parsley's backing was rejected after he made disparaging remarks about Islam, and Pastor John Hagee's blessing was rebuffed for making controversial comments about the Holocaust and Catholics.
During the Republican primary, former Massachussets governor Mitt Romney's Mormon faith was an issue for many in the conservative GOP base as some Christian leaders denied that Mormonism was a Christian religion.
Another GOP contender was former Arkansas governor Mike Huckabee, a former minister who had to deny that his December commercial intentionally included a cross-shaped glint of light in the background, in a sly appeal to evangelicals.