Updated

In May 1973, as the Watergate scandal metastasized from a bugging caper into a constitutional crisis, and the Nixon presidency hung in the balance, its leading voice on foreign policy expressed hope to the president that senior officials at the Department of Justice would be "wise enough" to keep the burgeoning investigation "away from the presidency."

Those comments to President Nixon by Henry A. Kissinger, then the national security adviser and soon to add to his portfolio the job of secretary of state, were among the 340 hours of secret White House tapes released by the Nixon Presidential Library and Museum in Yorba Linda, Calif., last week. The release marked the final installment in the National Archives' long-running series of such releases, dating back to the 1990s, with the result that roughly 82 percent of the 37th president's 3,700 hours of recordings are now available to the public. The remaining 700 hours have been withheld on national security grounds or to protect the privacy of surviving figures from the Nixon era.

Most historians agree that the Nixon tapes, along with the millions of cubic feet of documents generated by the president, his staff, and the executive branch agencies, make the Nixon years the most well-documented administration in the history of mankind. "[The tapes] remain perhaps the greatest treasure of information ever left by a president, as well as the most complex, controversial set of presidential records in U.S. history," historian Luke Nichter, a professor at Texas A & M University and co-founder of the website www.nixontapes.org, said on his website. "However, today these recordings remain relatively unexplored on non-Watergate topics."

When Kissinger met with Nixon on the morning of May 2, 1973, Nixon was fresh off one of the worst nights of his life. Two days earlier, he had wept at having to force, and accept, the resignations of his closest aides: White House chief of staff H.R. "Bob" Haldeman and domestic policy adviser John Ehrlichman. The pair, dubbed "the Berlin Wall" for the zeal with which they guarded access to the Oval Office, had become targets of the grand jury investigation into the Watergate break-in and wiretapping operation of May-June 1972, and the cover-up of that operation's origins, which had been consuming the energies of the president and his staff for the next nine months.

While Kissinger had exercised broad latitude over foreign policy from his perch at the National Security Council, and collaborated with Nixon on extraordinarily sensitive operations -- the secret bombing of Cambodia, the wiretapping of seventeen NSC aides and newsmen, among others - the newly poisonous atmosphere of Watergate left the two men wary of each other's motives and intentions. Though the existence of the taping system was known only to the president, Haldeman, and a handful of Haldeman aides, Kissinger on this day seemed to have a vague apprehension that he was being recorded -- and Nixon appeared eager to remind Kissinger how heavily involved the national security adviser had been in the leak investigations and wiretapping of the first term.

"Of course, you know Ehrlichman never told me what he was doing on any of these things," Kissinger told the president. He was referring to Ehrichman's role as head of the Plumbers, the covert group that investigated the leak of the Pentagon Papers and conducted both the Watergate break-in and the illegal entry targeting the psychiatrist of Daniel Ellsberg, the leaker of the Pentagon Papers.

"Doesn't make any difference," Nixon shot back. The president also raised the specter that one of the administration's operations that at that point was still secret -- and of great sensitivity to Kissinger -- would surface. "The India-Pakistan thing? That may crack sometime. We conducted one hell of an investigation in that time."

Nixon was referencing the so-called Moorer-Radford affair. In December 1971, the Plumbers determined that a young Navy stenographer, Yeoman Charles Radford, then detailed to Kissinger's NSC staff, had been systematically rifling Kissinger's briefcase and NSC wastebaskets and "burn bags," and had, over the course of thirteen months -- the wartime period of 1970-71 - secretly routed some 5,000 documents to his superiors at the office of the Joint Chieff of Staff, led at that time by JCS Chairman Admiral Thomas Moorer. The Plumbers also concluded that Yeoman Radford had leaked some of these papers -- including the classified minutes of NSC meetings on the Indo-Pakistani war that had been taken only four days earlier -- to syndicated columnist Jack Anderson, who won the Pulitzer Prize for publishing them.

Enraged at the military spying on himself and the president, Kissinger warned of serious consequences for the administration if the president did not act swiftly. Following the advice of Attorney General John Mitchell -- ultimately to be tried and convicted along with Haldeman and Ehrlichman in the Watergate case -- Nixon took no action against Admiral Moorer, except to warn him against continued spying; the yeoman was shipped out of Washington and wiretapped for six months; and security officers were installed at the NSC.

Now Nixon set out to remind Kissinger how much of his own work -- on Cambodia, the NSC wiretaps, the Moorer-Radford affair -- stood to figure in the mushrooming Watergate scandals and investigations. "The India-Pakistan [leaks], I don't know whether that'll break or not," Nixon told Kissinger. "That yeoman might [disclose it]. Anderson knows about that, because he knows the yeoman gave it to him. But the yeoman's now out -- where is he, on the West Coast?" "I don't know," Kissinger said softly. "I know they got him out of Washington."

"I didn't know that Hunt and Liddy existed at the time," Kissinger had reminded Nixon, in a reference to E. Howard Hunt and G. Gordon Liddy, the former CIA and FBI men, respectively, who plotted the Ellsberg and Watergate break-ins. "I never heard about Liddy until June 17th," the date of the arrests at the Watergate complex in 1972, Nixon countered. But he defended the steps taken to stop the unprecedented flor of classified information to the news media. "My God, Johnson was investigating all the time. Kennedy investigated. And so do we!"

Ultimately, Kissinger expressed fear that it was "too late," because the new attorney general, Elliot H. Richardson, "is in it for himself," and would not act in what Kissinger considered the nation's best interests.  "I know it's all very well to say that he should have a free hand, but you should give a free hand only to somebody who is wise enough to use it," Kissinger said. "Elliot will not necessarily agree that the major objective has to be: Keep it away from the presidency."

Later in the conversation, Kissinger undertook to reassure Nixon that he would survive the Watergate scandal. The national security adviser returned to this theme more than a month later. Talking with Nixon on the phone shortly before midnight on the evening of June 4, 1973, Kissinger explained why he thought it was so significant that Chinese leader Mao Tse-Tung had invited Nixon to visit China for a second time. "It means that they think that they are going to deal with you for the foreseeable future," Kissinger said.

No other president in history had ever needed such reassurance. Nixon did. He had already spent much of that day listening to his secret Watergate tapes, trying to make sense of who knew what about the scandal, and when. His comments while reviewing these tapes were themselves picked up by the voice-activated system - leading the Watergate prosecutors to call the June 4 tape "the tape of tapes" -- and would eventually figure prominently in the impeachment proceedings against him.

On August 9, 1974, Nixon resigned before three articles of impeachment that had been approved by the Democrat-controlled House Judiciary Committee reached the floor of the House for consideration there. On Sept. 8, 1974, Nixon's successor, Gerald R. Ford, pardoned him for all crimes he committed "or may have committed" in office.