If you were uncertain about whether or not Richard Nixon committed treason in 1968 by telling the South Vietnamese government to pull out of peace negotiations until after the election, there is no longer any doubt about it. Declassified recordings of LBJ’s phone calls make it clear that that is exactly what happened, and Johnson didn’t do anything about it because it would have required him to disclose that the NSA was bugging the South Vietnamese ambassador.
More newsworthy is the discovery that Johnson seriously considered flying to Chicago during the 1968 Democratic convention and entering his name for the nomination. Mayor Daley assured him that he would have the votes, but the Secret Service couldn’t guarantee the president’s safety, so the whole thing was called off. At least, that’s what the BBC’s reporting says, although that all seems implausible to me.