It was late at night in Russia, and Bill Clinton was troubled. The full weight of the Monica Lewinsky scandal had broken. In response he had made his televised admission of "inappropriate" behaviour. But, politically, it had not proved enough. The next day he was due, for the first time since his acknowledgement of sexual misconduct, to face the press.
His late-night vocabulary, however, was not that of the politician. "I need help. There are many sins in my life," he said to Campolo, a Baptist minister Clinton had known for more than five years because of the work of Campolo Ministries among the young urban poor.
"He used the word sins, he wasn't talking about inappropriate behaviour any more," Campolo today tells Michael Buerk in an exclusive interview in the first of a new series of The Choice on Radio 4. The President continued: "There are many sins in my life, and I need the strength to overcome them. I need to be connected to God... Would you be willing to help me?"
It took Campolo only a few seconds to decide. He has since had weeks to wonder whether he made the right decision - particularly as many right- wing Christians have now cut off funding to Campolo's work in the inner cities and among street children in one of the world's poorest countries, Haiti. Does he now worry that he has been used?
"Of course I do. There's not only the possibility but the probability that this is done in part to send a message to the nation," he says. And yet, in a way, that is appropriate. "In a sense sin was not only committed against Monica Lewinsky and against his family, but it was a sin that left the whole nation disappointed and you need to make confession to all of those that you have hurt. So... I guess I am being used." But he then points out that, as the Apostle Paul says, "some people come to the gospel out of strife... but I don't care so long as they are willing to hear the word of God and listen to wise counsel."
The key question, of course, is whether Clinton is sincere in that public contrition and whether he is prepared to listen to wise counsel when it is of a purely spiritual rather than a political nature.
Is Clinton sincere? "People say it's not sincere and that the only reason he's repenting is because he's got caught," says Campolo. There are only two kinds of sinners, he reckons: those who have been publicly exposed - and the rest of us.
Campolo is one of a team of three evangelical ministers acting as what the Americans call a "spiritual accountability" circle for the President. "Our job is not to say whether it is politically expedient. However, we do say: `We think you ought to do what's right whether it is politically expedient or not.' And I think that on 11 September he did just that."
That was the date on which Clinton attended a prayer breakfast at the White House where he confessed he had sinned and begged for forgiveness. He also announced that he was forming his "spiritual accountability" circle, which was to include Campolo, who was present at the meeting. Revealingly, Campolo tells Michael Buerk that this was Clinton' s "real confession".
He does not expand in today's programme, but in evangelical Christian circles it is claimed that the repentance speech delivered that morning was the one originally drawn up by Campolo and the others for Clinton's TV appearance. However, the fulsome admission of contrition was dropped at the insistence of the White House spin doctors in favour of the much- mocked statement about "inappropriateness".
Acting as pastor to Clinton is clearly a hazardous pilgrim's progress. Campolo had said that he would be "upset no end" if it turned out Clinton had committed adultery. So how did he feel when the truth came out? "All those who love the President - his wife, his daughter, his friends, are upset no end. We wanted to believe the best - and when the truth broke we were hurt," he said, acknowledging that there was some "confrontational stuff" in his counselling sessions with Clinton.
But in the end, he says, it is clear that "what grieves the President most is not what it has done to him, but what it's done to his daughter and what it's done to his wife and what it's done to his friends. He weeps over this."
None of which is a new experience for a man of the cloth. "Pastors do this all the time... not only do I find myself betrayed by many of the people I counsel and stake my life on, but I always have to remember that Jesus was betrayed by me," he said. "If I am only going to put my arms around people who are righteous, I will live a very, very lonely life. I do not back sin... but I love the sinner even as I weep over their sin."
Not everyone is so generous. Some 85 per cent of US evangelicals are Republicans. When Campolo made public his decision a significant number of those who finance his ministry announced they were withdrawing funding. Invitations to preach were withdrawn. He was surprised and hurt - not so much by the vehemence he encountered as by the willingness of Clinton's enemies to penalise the poor and the dispossessed to exact their revenge.
"I seldom sleep a night any more. I walk the floor, praying and saying: `Is this to mean that we have to cut back on feeding programmes and education to some of the neediest people on the planet?' "
His programme assists 80 schools in Haiti for "slave" children from families so poor that they give their children away. He constantly asks: "Why would anybody cut off support to desperate children simply because Tony Campolo may have done the wrong thing?"
He adds: "Self-doubt overtakes me at that point... Is it really worth it to see people hurt in Haiti because I'm trying to respond to somebody in the White House. But I must do what I must do - and weep over the pain that my decision may have brought to others and constantly be asking: Did I do the right thing?"
`The Choice' with Michael Buerk is on Radio 4 today at 9am