Nixon betrayal far worse than GOP Iran letter: Column Republican nominee sabotaged Vietnam peace talks before he was elected president.

Ray Locker | USA TODAY

The warning letter by 47 Republican senators to Iran's leaders about any deal reached with President Obama spurred the White House to claim the senators had interfered with ongoing negotiations. It was a bold departure from the previous practice, but it falls short of what some are calling treason.

It also does not rise to the same level as Richard Nixon's interference with the Paris Peace Talks in the fall of October 1968, when then-President Lyndon Johnson thought he had a deal that could end the Vietnam War, or at least speed the U.S. departure from Vietnam. That, presidential records show, put Nixon's fingerprints on a stunning interference with the peace talks.

By then, the United States had bombed North Vietnam for more than three years. The so-called Rolling Thunder raids turned much of the country into a smoldering ruin. However, they did little to stem the North Vietnamese and Viet Cong war effort in South Vietnam. Communist troops dominated wide swaths of that country, and their bold offensive during the Tet holiday period that winter, while eventually unsuccessful militarily, damaged U.S. morale.

The United States, North Vietnam and the Viet Cong started meeting in Paris in May 1968 to find a way to end the war. Progress in the talks was painstakingly slow. For months, the negotiators argued over the shape of the conference table, and the communists resisted the presence of South Vietnamese negotiators because they considered them only representatives of an illegitimate U.S. puppet regime.

But the U.S. team managed to win a concession that had the potential to break the talks open. The United States would stop bombing North Vietnam if it agreed to three terms — that the North Vietnamese respect the demilitarized zone separating the two countries, allow the South Vietnamese to join the Paris talks, and stop the artillery barrages on southern cities.

Eventually, Hanoi agreed, and Johnson stopped the bombing, just days before the November election that saw his vice president, Democrat Hubert Humphrey, opposing Republican Nixon and independent George Wallace.

Johnson had briefed Humphrey, Nixon and Wallace about the bombing halt and the reasons behind it. Nixon knew what the North Vietnamese had agreed to do. Nixon also knew that his campaign operatives, led by manager and future Attorney General John Mitchell, had used a supporter, Chinese-American activist Anna Chennault, to tell the South Vietnamese government to refuse to go to Paris because Nixon would give South Vietnam a better deal if he won the election and not Humphrey.

South Vietnamese President Nguyen Van Thieu had plenty of doubts about any deal with North Vietnam. He knew his country could not win on the battlefield without the 565,000 U.S. troops fighting the war and the huge amounts of U.S. aid that propped up South Vietnam. Thieu was ill disposed to any kind of deal, but he was also susceptible to the enticements from the Nixon campaign.

Nixon's problem was that Johnson knew what the Nixon campaign was doing. The National Security Agency monitored Chennault's talks with the South Vietnamese ambassador to the United States, Bui Diem, and Diem's calls back to Saigon. Johnson was livid.

"Now I'm reading their hand," Johnson told Republican Sen. Everett Dirksen on Nov. 2, 1968. "I don't want this to get in the campaign. And they oughtn't to be doing this. This is treason."

Dirksen said he would call Nixon directly to tell him Johnson's concerns and then have Nixon call Johnson.

"I know this," Johnson said, "that they're contacting a foreign power in the middle of a war."

Nixon called Johnson on Nov. 3, and lied.

"I just want you to know that I'm not trying to interfere with your conduct of it," Nixon told Johnson. "I'll only do what you and (Secretary of State Dean) Rusk want me to do. But I'll do anything."

"Well, that's good, Dick," Johnson replied, although he knew from multiple sources that Nixon was lying.

By Election Day, it was clear Johnson's long shot had failed. Thieu kept his people home. Nixon won the election and then spent his time as president trying to cover up his involvement in scuttling the talks. Memos from White House aides, including Henry Kissinger, warned that any White House investigation into the bombing halt would only cause leaks and potentially embarrass the White House.

Monday's Senate letter to Iran doesn't meet the Nixon standard because it came in an open forum. It was little different than an op-ed column in a newspaper. Nevertheless, it represents a bold and potentially destructive chapter in the ongoing relationship between the Obama administration and the Republican Congress. But today's Republicans, unlike Nixon, did so openly, and the White House has had the chance to weigh in.

Ray Locker is the Washington enterprise editor of USA TODAY and author of Nixon's Gamble: How a President's Own Secret Government Destroyed His Administration , to be published in October.

