The BBC has a good piece on the '68 elections, Nixon's torpedoing of the Vietnamese peace talks that Johnson had underway at the time, and the call by Humphrey to not make this public, because...
Humphrey had been told by his pollsters that he had the election won. Of course he didn't, and Nixon as Prez went on to continue the war for five more years. All this is detailed in the recently released Johnson tapes.
In addition to the craziness of Nixon's interference in the negotiations with the North and South Vietnamese, and the resulting deaths of tens of thousands of Cambodians, Laotians, Vietnamese and Americans, is the tantalizing notion that Humphrey, perhaps with better polling, might have won the election. One of the most interesting paragraphs of the article reads:
"The president [Johnson] did let Humphrey know and gave him enough information to sink his opponent. But by then, a few days from the election, Humphrey had been told he had closed the gap with Nixon and would win the presidency. So Humphrey decided it would be too disruptive to the country to accuse the Republicans of treason, if the Democrats were going to win anyway."
The article also details a number of one-step-away-from-happening political events, like Johnson's almost appearance at the Chicago Democratic Convention, avoiding the demonstrators (including me) by landing on the roof of the convention hotel. Wild stuff. And horrible lost opportunities to have the world be a better place.
11:39 AM PT: Composting's piece on Rethinking Watergate points to this business as a precursor to Watergate. Great piece.