Egil Krogh tells his story in "Integrity"

President Richard Nixon, much like George W. Bush, believed in an expansive interpretation of executive power, especially in the context of "national security." Nixon once expressed an almost imperial sense of executive infallibility, telling interviewer David Frost that "when the president does it, it's not illegal." Nixon had no qualms about ordering illegal surveillance of political opponents or burglarizing opponents' offices in search of evidence with which to discredit them. Nixon's views led to Watergate, and his eventual resignation.

Egil "Bud" Krogh worked for Richard Nixon, and went to prison trying to do his bidding. Yet unlike Nixon himself or Nixon's other White House conspirators, Krogh did the unthinkable: He took full responsibility for his illegal actions and pleaded guilty to violating his victims' civil rights. In retrospect, Krogh admits that "my absolute loyalty to President Nixon personally and to his view of the national security threat had skewed my perspective. This kind of absolute loyalty lacked integrity...." Krogh rejected Nixon's expansive view of national security "as a blanket justification for any type of conduct."

Integrity is Krogh's enlightening, straightforward description of how he went wrong and how he's tried to make it right. It begins with the divisiveness of an unpopular war and a president trying to defend his policy. When military analyst Daniel Ellsberg leaked the top-secret Pentagon Papers (a pessimistic view of US involvement in Vietnam) to The New York Times in 1971, Nixon went ballistic and wanted Ellsberg punished.

In a July 1971 meeting with Krogh's boss John Ehrlichman (counsel to the president), Nixon described his plan to undermine Ellsberg: "I really need some [S.O.B.] ... who will work his butt off and do it dishonorably," said Nixon. "We are going to use any means. Is that clear?" In order to destroy Ellsberg, Nixon needed somebody loyal who wouldn't ask troubling questions and could keep his mouth closed.

Ehrlichman gave the assignment to Bud Krogh, telling him it "had been deemed of the highest national security importance by the president." Krogh, a former Navy officer who had babysat Ehrlichman's kids, soon hired G. Gordon Liddy and E. Howard Hunt to handle operational issues. Initially, Krogh believed both patriotism and loyalty justified his conduct. In an effort to smear Ellsberg, a burglary of his psychiatrist's office was carried out, after being approved by Ehrlichman. The burglars broke in on Aug. 11, 1971, but found nothing of use.

While Krogh was not part of the later Watergate break-in, his role in the Ellsberg-inspired break-in came out as part of the Watergate investigation, despite White House efforts to cover it up. Under federal indictment, Krogh decided to plead guilty: "I came to accept that I could no longer defend my conduct." Even more surprisingly, Krogh refused to barter his testimony against other indicted officials in order to get a lighter sentence. Krogh would take full responsibility, go to prison, and do his time: "[M]y final decision to plead guilty was an important step in restoring some of my integrity," he writes.

After Krogh was released from prison, he visited Ellsberg's psychiatrist and personally apologized for his role in the break-in. He also met with Nixon, who adamantly refused to admit any wrongdoing: "[Nixon] told me that he did not feel guilty." Postprison, Krogh rebuilt his life and restored his integrity. He taught college and worked for a congressman, then returned to practicing law.

Alas, Krogh believes the lessons of the Nixon years have not been heeded. In 2001, Krogh wrote a memo to members of the new Bush administration, explaining how the Nixon White House had experienced "a major breakdown of integrity" through unquestioning loyalty to the president and blind faith in blanket assertions of national security.

Krogh feels his warnings have been largely ignored: "I have been disappointed to observe the Bush administration," writes Krogh, who bemoans a return to a Nixonian "imperial presidency" as evidenced by secret surveillance programs carried out by the National Security Agency and Bush's murky constitutional defense of torture in places like Guantánamo Bay, Cuba.

Krogh has obviously learned his lessons from the Nixon years, and his accessible account is impressively direct, thoughtful, and free of the usual, logic-twisting political justifications for wrongdoing. It's bracing to hear how one man learned from his mistakes working in the White House. And yet, at the same time, it's deeply troubling to think that those mistakes, bred from blind political loyalty and unquestioning reliance on invocations of national security, may keep on repeating themselves.

• Chuck Leddy is a member of the National Book Critics Circle and writes frequently about American history.