The Richard Nixon legacy has over the years been on the road to at least a partial recovery. From the ashes of the Watergate scandal and the resignation, talks about opening up China, the Clean Air Act and the Clean Water Act have rehabilitated him by some amount.
That recovery is likely to come to a screeching halt in the face of newly-declassified documents from the Lyndon B. Johnson Presidential library. I will leave you to dig through the details provided by the BBC and Middle East Online, but the gist is this:
*According to the tapes, Johnson had evidence that Nixon was sabotaging the Paris Peace Talks in 1968, an effort to end the Vietnam War. Evidence that Nixon had done so has actually already surfaced, though only in 2008, after nearly all the principal actors had died. Through senior campaign advisor Anna Chennault, the Nixon campaign communicated to the South Vietnamese that they should withdraw from the talks and refuse to deal with Johnson, because Nixon would offer them a better outcome should he be elected. When the talks failed, Nixon then went to the voters and crowed about how Johnson's peace talks were going down in flames, an action Johnson considered treason, but an argument the voters bought. (And then Nixon proceeded to expand the war and bomb Cambodia in an effort to give them that outcome... which, ultimately, he failed to do.)
*Johnson, with evidence in hand, considered entering the 1968 campaign- the one mentioned here two years ago that he didn't enter because the primary polls had him getting clobbered- and using his evidence as the lynchpin of that campaign. He was wavering, though, because releasing the evidence came from sources he didn't want the public- or the Vietnamese- to know were being bugged. Also, given that he had already pulled out of the race because of polls, he was only going to enter based on polls, because this was Lyndon Johnson we're talking about. Eventually, he was told that he would have the support to enter the race, but the Secret Service told him that his safety could not be guaranteed. Johnson ultimately stayed on the sidelines, the information was shelved, and Nixon won.
*After re-election, Nixon was informed by FBI head J. Edgar Hoover that those tapes existed. Nixon turned the White House upside down to find them, but Johnson had had them removed; they were in the hands of Walt Rostrow, one of Johnson's national security aides. Nixon- or rather, Henry Kissinger and J.R. Haldeman- were only able to recreate what exactly was on the tapes. Nixon never stopped looking for the originals, as he considered them to be even more of a blow to him than the Pentagon Papers released in 1971... and in 1972, his search turned to the Watergate Hotel.
Short story even shorter, Nixon had the Vietnam War dragged on six additional years for the sake of winning the 1968 Presidential election. The events from October 1968-April 1975 need not have happened.