From BBC News:
The Lyndon Johnson tapes: Richard Nixon's 'treason'

This is not new information.  As the article states it was known by journalists since 1994, and I've read it in a few different places now.  (Christopher Hitchens mentions it in The Trial of Henry Kissinger.)  But it appears the tapes were officially declassified  in 2008, and the BBC 4 is doing a program on it.  So apparently it is not in dispute anymore that Nixon sabotaged the 1968 peace process to win the elections.

The amount of blood on Nixon's hands just to win the election is staggering to contemplate.  This means that every American soldier killed since 1968 died unnecessarily (22,000, according to the BBC).  Not to mention all the millions of Cambodians, Laos, and Vietnamese killed.  (And yes, the number is in the millions.)
Plus the massive bombing of Cambodia under Nixon and Kissinger which lead to the destabilization of the country and the Khmer Rouge could also have been avoided.

All just to win an election...