On the eve of his election in 1968, Richard Nixon secretly conspired with the South Vietnamese government to wreck all-party Vietnam peace talks as part of a deliberate effort to prolong a conflict in which more than 20,000 Americans were still to die, along with tens of thousands of Vietnamese and Cambodians.

The devastating new charge against Nixon, which mirrors long-held suspicions among members of President Lyndon Johnson's administration about the Republican leader's actions in the autumn of 1968, is made by the authors of a new study of Nixon's secret world in the latest issue of Vanity Fair magazine.

"The greatest honour history can bestow," reads the inscription on Nixon's black granite tombstone in California, "is the title of peacemaker." But if the charges by authors Anthony Summers and Robbyn Swan are correct, Nixon better deserves to be called a peacewrecker than peacemaker.

At the heart of the new account was Nixon's fear that Vietnam peace efforts by President Johnson in the run-up to the November 1968 US presidential election could wreck Nixon's bid to oust Hubert Humphrey, the Democratic candidate, and capture the White House.

Nixon's response to Johnson's efforts was to use a go-between, Anna Chennault, to urge the South Vietnam's president, Nguyen van Thieu, to resist efforts to force them to the peace table.

Nixon's efforts paid off spectacularly. On October 31, Johnson ordered a total halt to the bombing of North Vietnam, the precondition for getting the North and their Vietcong allies to join the talks. Two days later, under intense secret urgings from Nixon and his lieutenants, Thieu announced his government would not take part. Less than a week later, Nixon was elected president with less than a one-point margin in the popular vote over Humphrey.

Playing with US lives



The Vanity Fair article charges that Johnson knew what was going on. Intelligence reports to the president told him that Nixon and his running mate, Spiro Agnew, were playing politics with the lives of US soldiers. "Had it been made public at the time, it would surely have destroyed Nixon's presidential hopes at one stroke, and forever," the authors write.

Johnson offered Humphrey the chance to go public about Nixon, but Humphrey was afraid that the charges would be seen as election dirty tricks. Once Nixon had won, Johnson again contemplated revealing what he knew, but decided the national interest precluded it.

In the weeks running up to the election, Nixon's public stance was that, if elected, he would bring the war to an end more effectively than Humphrey. He promised not to interfere with pre-election peace efforts, pledging that neither he nor Agnew "will destroy the chance of peace".

In reality, however, Nixon used his campaign manager, John Mitchell, later his disgraced attorney general, to use go-betweens to encourage Thieu to believe he would get a better deal under a Nixon administration and to boycott the putative talks. Nixon constantly denied that he was conspiring with Thieu against the US government, but the release of previously classified FBI files used by the authors show this was exactly what he was doing.

Chennault, Nixon's main go-between with the South Vietnamese, was a right-wing Republican society hostess who was Chinese born and lived in a newly constructed Washington apartment complex - named the Watergate. She was vice-chairman of the Republican election finance committee and an inveterate lobbyist on behalf of right-wing and pro-American Asian interests.

Chennault regularly passed messages to Mitchell and Nixon during 1968 and they urged her to put pressure on the South Vietnamese leader to create delays and to refuse to take part in the peace talks.

US embassy spy operations, including wiretaps of Thieu's offices, revealed the Thieu-Nixon connection in October and Johnson was briefed about them. One message from Thieu's ambassador in Washington, Bui Diem, told Thieu: "Johnson and Humphrey will be replaced and then Nixon could change the US position."

When Thieu pulled out of the talks, Johnson exploded. He told his advisers that he would go public on a development that could "rock the world". That development, he said, was Nixon's "conniving" with the Thieu regime. An adviser had told Johnson that Nixon was "trying to frustrate the president by inciting Saigon to step up its demands". "It all adds up," Johnson told his advisers.

On October 31, with the bombing halt announced, Mitchell rang Chennault and told her: "Anna, I'm speaking on behalf of Mr Nixon. It's very important our Vietnamese friends understand our Republican position and I hope you have made that clear to them. Do you think they have decided not to go to Paris?"

Chennault made contact with Thieu once again. An FBI report said that she "contacted [the] Vietnamese ambassador and advised him that she had received a message from her boss (not further identified) which her boss wanted her to give personally to the ambassador. She said the message was that the ambassador is to 'Hold on, we are gonna win' and that her boss also said 'Hold on, he understands all of it'."

On November 2, three days before the election, Thieu announced that South Vietnam would not attend the talks.

Johnson's bad relations with J Edgar Hoover at the FBI meant that Hoover, a Nixon ally, did not tell the president everything that his agents had unearthed. Even so, Johnson had learned enough to speak to Nixon by phone the weekend before the election. Nixon denied Chennault was working for him. When the phone was put down, it was later reported, "Nixon and his friends collapsed with laughter".

Johnson was certain Nixon was lying, and told Humphrey what was going on. Humphrey learned about the Nixon-Thieu contacts while he was travelling by plane to a campaign. "By God, when we land I'm going to denounce Thieu. I'll denounce Nixon. I'll tell about the whole thing," he shouted to aides. But he never did.

In the five weeks leading up to the election of 1968, 960 Americans were killed in Vietnam. In the years to come, under Nixon, 20,763 more US soldiers would die.

"What the Nixon people did," the US diplomat Richard Holbrooke, then attached to the advance US guard to the Paris talks, tells Vanity Fair, "was perhaps even a violation of the law.

"They massively, directly and covertly interfered in a major diplomatic negotiation, probably one of the most important negotiations in American diplomatic history."

1957 Beginning of communist insurgency in South Vietnam

1959 Weapons and men from North Vietnam begin infiltrating the South

1960 US aid to the South Vietnamese president, Ngo Dinh Diem, increased

1962 President John F Kennedy provides US military advisers to South Vietnam (12,000 by end of year)

1963 Viet Cong, the communist guerrillas operating in South Vietnam, defeat units of ARVN, the South Vietnamese army. President Diem overthrown

1964 North Vietnamese patrol boats fire on the US destroyer Maddox in the Gulf of Tonkin, triggering start of US bombing raids on North Vietnam

1965 US troops in Vietnam number 23,000 at start of year

1966 400,000 US troops in Vietnam, rising to 500,000 in 1967

1968 Tet Offensive - a combined assault by Viet Cong and North Vietnamese army on US positions - begins. More than 500 civilians die in My Lai massacre

March 31 1968 President Lyndon Johnson (below right) announces on television that bombing north of the 20th parallel will stop and that he will not seek re-election in the fall. Hanoi responds by de-escalating its insurgency efforts, and in October Johnson orders total halt to bombing. US and Hanoi agree to preliminary peace talks in Paris

1969 President Nixon draws back US ground troops from Vietnam

1970 Nixon's national security adviser, Henry Kissinger, and Le Duc Tho of the Vietnamese politburo start talks in Paris

1973 Ceasefire agreement. Withdrawal of US troops completed by March

1975 North Vietnamese troops invade South Vietnam and take control of the whole country after South Vietnam surrenders

April 1975 Last members of US embassy staff evacuated by helicopter from roof of embassy

Human toll 3m military and civilian Vietnamese. 58,000 Americans

Research: Jason Rodrigues