Not long after he became the presumed Republican nominee, John McCain flew to New Orleans to face a skeptical audience -- conservative leaders of the Council for National Policy.

A questioner zeroed in on a topic McCain rarely addresses on the campaign trail, asking him to explain his faith in God.

McCain, an Episcopalian who attends a Baptist church in Phoenix, turned to a well-worn tale of the guard he met when he was a prisoner of war in North Vietnam. The man once loosened the ropes binding McCain, and later shared his Christian faith with McCain by silently sketching a cross in the prison yard with his sandal.

The story played well in an ad before the New Hampshire primary, but it was deeply disappointing to many at the New Orleans gathering, conservative activist Richard Viguerie recalled.

"He blew that question off by telling us about the faith of his jailer," said Viguerie. "It was very obvious to those three or four hundred conservative leaders there. . . . The vast, vast majority of them were either sitting on the sidelines or unenthusiastic about his impending nomination and he didn't move a single person."

McCain's reticence about raising the subject of his faith in public is all the more noticeable as Sens. Hillary Rodham Clinton and Barack Obama have spoken up about their beliefs as they campaign for the Democratic nomination.

The secular language of McCain's speeches, often rooted in patriotic themes of duty, honor and service, is also a striking contrast to that of President Bush, who bonded with evangelicals by threading religious language through his speeches and speaking about how faith rescued him from his struggles with drinking.

Even as some prominent Republican leaders have urged McCain to talk more about his faith to woo evangelicals, the candidate said in a recent interview that he would try to be inclusive when he talks about religion.

"People should know the tenets of my faith and my beliefs," McCain said when asked about the contrast between Bush's language and his own. But, he said, "you want to be careful to not create an appearance -- whether it's intended or not intended -- of imposing the specifics of your beliefs on others."

McCain is most comfortable talking about his religious awakening during his 5 1/2 years in captivity, where his connection to God grew stronger and he served as "room chaplain" for a small group of prisoners.

In his early life he was influenced by his "deeply religious" father, who relied on his faith in a long struggle with alcoholism. Prayer and church became an "ingrained part" of McCain's life at his high school, where he attended chapel every morning and on Sunday evenings, even after church, he says.

McCain says in those days, he was a self-absorbed rule-breaker who became a hard-partying naval aviator. It was not until after his plane was shot down over Hanoi in October 1967, he wrote in his memoir, "Faith of My Fathers," that he learned to "grasp" faith tightly. In solitary confinement, he prayed "more often and more fervently than I ever had as a free man."

"I was very slow in maturing," he said aboard his campaign plane. "I knew right from wrong; I knew the Bible; I knew the Nicene Creed and the Apostles' Creed and the tenets of my faith. And although I neglected them, the time came that I could fall back on them as a net, as a way of salvation, literally."

Often his faith helped him "get through another minute," he said. At the same time, McCain said, he learned to be "careful not to ask God to do things that were temporal rather than spiritual."

In McCain's first talk as chaplain, he cautioned fellow prisoners not to pray for their release -- reminding them of a parable in which Jesus was asked whether it was right to pay taxes. "He held up the coin and said, 'Render unto Caesar that which is Caesar's and unto God that which is God's,' " McCain said, recalling his lecture. "The point of my talk was we were doing Caesar's work when we went into combat, so we really shouldn't ask God" for release.

That lesson guided McCain not to pray for his own personal success. "I pray to do the right thing so I won't look back in regret or embarrassment or even shame that I betrayed my principles and my faith," he said.

McCain began attending a Baptist church after marrying Cindy McCain in 1980 and moving to Arizona. At North Phoenix Baptist Church, which is affiliated with the Southern Baptist Convention, McCain was attracted to the pastor's message "that we're all sinners, but we can benefit from God's grace if we recognize those sins and move forward," he said.

Although some religious leaders contend that McCain has not said enough about how his faith influences his positions, his stance on abortion is clear. McCain is a staunch opponent. He said that his view that life begins at conception is based "to some degree" in his religious faith.

He has angered some religious conservatives by supporting federal funding for stem cell research and with his nuanced position on gay marriage. (He opposes same-sex marriage, but does not believe a constitutional amendment is necessary because he sees it as a state issue.)