HARRISBURG, Pa. — They called it the church riot.

Sen. John McCain, who is known for his reticence and even discomfort invoking faith on the campaign trail, was once dubbed a "Hell's Angel" for rioting against his captors in Vietnam in order to hold Sunday church services.

It is a story unknown by a public still getting to know McCain and searching for shared values with the candidates. This Saturday, McCain and Sen. Barack Obama will separately answer questions from evangelical leader Rick Warren at his Saddleback Church in Southern California.

In an extended interview, McCain talked about how his faith was tested during his years as a prisoner of war from 1967 to 1973, said God must have had a plan for him to have kept him alive, and reminisced about his appointment as informal chaplain to his cellmates.

"There were many times I didn't pray for another day and I didn't pray for another hour — I prayed for another minute to keep going," said McCain, who was brought up Episcopalian but now worships at North Phoenix Baptist Church, a Southern Baptist church. "There's no doubt that my faith was strengthened and reinforced and tested, because sometimes you have a tendency to say, 'Why am I here?' "

McCain said his faith in God informs his decisions on issues of public policy. Christian conservatives are skeptical of McCain's commitment to many of the issues they care about, such as abortion and marriage. They have also been disappointed in his embrace of embryonic stem cell research. But McCain said he wrestled with that decision and hopes technology soon renders it obsolete.

Although polling suggests voters view faith as an essential ingredient in a president, McCain has never been a candidate to invoke God or dwell on religion. "In our case, faith is private," said his wife, Cindy, adding that once voters get to know him, "they will know he is a man of faith."

In Vietnam, McCain's fellow prisoners say their faith was a matter of life and death. "We knew we had to have some belief greater than ourselves," said Orson Swindle, a Marine captain who spent six years in captivity.

The prisoners had developed a tap code system for communicating through the walls. Through that tapping, "we decided we needed to be all on the same sheet of music at least one time during the week," Swindle said.

Cough for church

The prisoners decided that every Sunday, after they had eaten their rice, the highest-ranking officer would cough loudly and say the letter 'c' for church. The prisoners would then say the Pledge of Allegiance, the Lord's Prayer and the 23rd Psalm. The psalm was said in plural: "Yea, though we walk through the valley of the shadow of death we will fear no evil."

Prisoners used diarrhea pills mixed with cigarette ash—or charcoal or dirt—to write lines of Scripture and surreptitiously share them.

The church riot erupted after U.S. Special Forces raided a site about 40 miles from Hanoi trying to rescue prisoners who, it turned out, were no longer there. The Vietnamese, fearing more such raids, rounded up American POWs and moved them from other outlying camps into Hanoi. That meant an end to isolation, as dozens of prisoners were packed together.

"We agreed that we were going to have a church service and told the Vietnamese, and they said no," recalled fellow prisoner Bud Day. But on Feb. 12, 1970, the prisoners went ahead anyway, holding a service and singing songs.

"The Vietnamese broke in and seized the people who were standing against the wall doing the service," Day said. "They marched them out of the room at gunpoint. So I stood up and started singing 'The Star-Spangled Banner,' 'God Bless America,' 'My Country 'Tis of Thee' and every song we could think of."

The Vietnamese stormed back in, putting a definitive end to the service.

"We wanted to actually just have a chance to do what we felt was a fundamental human right ... and we got spiritual comfort from being able to worship together," McCain said. "We thought, look, if we're going to be together, then we're going to stand up. ... They'd done so many bad things that we weren't nearly as afraid of them as maybe we would have been if a lot of us hadn't gone through what we'd gone through."

For their efforts, guards moved McCain, Day, Swindle and about 20 others to a camp where the conditions were unsanitary and prisoners fell ill.

About six months later, they were back in the ironically named Hanoi Hilton, and Day, the senior officer, chose McCain as the group's chaplain. His first lesson — he doesn't like to call them sermons — recounted the biblical story of the man who asked Jesus whether he should pay taxes. Jesus replied, "Render unto Caesar what is Caesar's, and render unto God what is God's."

McCain's point was that the prisoners should not pray for freedom, nor for harm to come to their captors.

"What I was trying to tell my fellow prisoners is that we were doing Caesar's work when we got into prison, so we should ask for God's help to do the right thing and for us to get out of prison if it be God's will for us to do so," McCain said. "Not everybody agreed with that."

Swindle said he understood McCain's talk to mean that "the God we had come to know wasn't going to wave a magic wand and 'poof,' we would all be free. The God we knew would give us the strength to endure what we had to do, and it was up to us to take that strength and knowledge and do what we had to do."

McCain also recalls a Christmas service he orchestrated. A week before the holiday, McCain's guards let him out of his cell and gave him a pencil, a piece of paper and a King James Bible. He copied sections of Matthew, Mark and John describing the birth of Christ so he could read them aloud while other POWs sang "It Came Upon a Midnight Clear" and "Silent Night."

"I recall it as if it happened an hour ago," said McCain, sitting in a chair in a suite overlooking the Susquehanna River near the end of a day. "It was cold, the guards were looking through the windows at us, the room was dimly lit because of the light bulbs [that] were in each corner. These guys had beautiful voices, I'm telling you. One was a bass, one was a tenor. It was one of the most beautiful experiences I ever had."

'I'm not a fatalist'

The men became tearful. "It wasn't because they were sad," McCain added. "It was because they were so happy to be able to celebrate Christmas with fellow Americans."

McCain's friends say they believe God had a plan for him, allowing him to survive to put him on the cusp of the presidency. He, too, acknowledges that idea, though cautiously.

"I can't help but feel like that to some extent, and I'm not a fatalist," said McCain. "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."

jzuckman@tribune.com