Once he was Chuck Colson, the tough-talking chief of the White House domestic intelligence arm. Bright and abrasive, loyal beyond the bounds of propriety, Colson was widely regarded in Washington as the shrewdest and most ruthless of the men close to the President. "Colson would do anything," Richard Nixon once told presidential counsel John Dean.

Recently, shaken and subdued, the 42-year-old Colson reached the end of the road down which the President's wishes had apparently taken him. Pleading guilty in federal court to a charge of attempting to obstruct justice by influencing the trial of Dr. Daniel Ellsberg, Colson was sentenced to one-to-three years in prison—the toughest punishment yet handed down to any former administration official. Yet even at the moment of sentencing, Colson continued to profess that a profound spiritual revolution had taken place in his life. "I've committed my life to Jesus Christ," he explained to newsmen outside the courtroom. "I can work for the Lord in prison or out of prison, and that's what I intend to do."

To many in his legion of political enemies, Colson's conversion to evangelical Christianity seemed both convenient and highly improbable. Private cynicism abounded, but few were willing to challenge him outright. "I haven't run into many people who doubt my sincerity," says Colson. "Many more people come up to me and say 'Tell me how to do it!' Harold Hughes has had the same experience with alcoholics." Hughes, the reformed alcoholic who became senator from Iowa, is a member of Colson's Washington prayer group. Initially a skeptic, he is now a staunch defender of the sincerity of a man who once despised him politically. "I knew he was a liberal Democrat the White House opposed," says Colson. "Then he was the enemy. Now, except for my family, he is the closest friend I have in the world."

Colson's withdrawal from partisan combat signals the close of a hectic career. The only child of a Boston attorney and his wife, he joined the Marines after graduation from Brown University in 1953, and quickly became the corps' youngest captain. Later he joined the staff of U.S. Senator Leverett Saltonstall of Massachusetts and became—at 27—the youngest administrative assistant on Capitol Hill. By 1969, when he left private practice to become an aide to the President, he was earning an annual six-figure salary. It was an impressive list of worldly accomplishments, but Colson looks back on it now with bemusement. "I was just a man in a hurry," he says. "I went to law school nights while I was working days. I did everything double time, so I never really had time for reflection. I was always trying to get to the top of the next mountain so I could impress people with how good I was. Now I'm going to take time to really decide what I want to do with the rest of my life." He expects to be disbarred at least temporarily, but says he hasn't worried yet how he'll make a living after jail. His life is full of more spiritual concerns. "If you can change men's hearts you can do more," the ex-White House aide now says. "Through history, many Presidents were empty in regard to the real impact they made on human affairs."

Although Colson is now a convicted felon, he continues to deny involvement in Watergate. He believes he has been badly misrepresented in the press, and his purported arrogance blown out of proportion. In one minor but well-remembered incident, he maintains, he never seriously proposed "walking over" his grandmother, as he was quoted in the 1972 campaign, in the interest of getting the President reelected. "That was a throwaway line," he sighs. "No one understands my sense of humor. I've always joked with a reverse twist."

Colson's latest reversal, however—unexpectedly pleading guilty after countless protestations of innocence—is unlikely to provoke much humor at the White House. By bargaining away his freedom, he has committed himself to testifying in other Watergate-related cases, and government prosecutors are expecting some dividends. "Colson didn't promise to hand up anybody," says one prosecution source. "But he can't take the Fifth. He's got to produce documents and evidence. And he's got to know a lot. He talked to the President all the time."

Though Colson has already implicated the President in the crime he himself pleaded guilty to, his Nixon loyalty appears largely intact. He felt close enough to Nixon to discuss his religious conversion with the President—"a man," Colson says, "with more spiritual feelings than people realize, but he doesn't like to mix them with politics." What triggered his own conversion, Colson says, was a passage on pride in Mere Christianity, a book by the English theologian C.S. Lewis. "Pride leads every other vice," Lewis wrote. "It is the complete anti-God state of mind." Although Colson had been brought up as an Episcopalian, and later studied Christian Science and Roman Catholicism, he had never experienced such a moment of revelation. "I had an experience that is very close to what you see in the movies," he recalls, "when someone is dying and their whole life parades before them." Although he made his personal commitment to Christ last summer, Colson says, his conversion was revealed in the press only after he was discovered attending a White House prayer breakfast in December. Later, when Colson was indicted, a member of his personal prayer group tried to ease his depression. "Well, Chuck," the friend observed consolingly, "just remember we got a Christian in the news."