Texas ? In the last months of his administration, President Lyndon Johnson voiced worry over the Vietnam peace talks and stridently suggested that associates of Richard Nixon were attempting to keep South Vietnam away from the table until after the 1968 election, recordings of telephone conversations released Thursday show.

“This is treason,” Johnson said, referring to people close to Nixon, during a conversation with Senate Republican leader Everett Dirksen.

The Democratic president never accused the Republican who would succeed him of treason, but said, “If Nixon keeps the South Vietnamese away from the (peace) conference, well that’s going to be his responsibility.”

Nixon spoke with Johnson in another recorded phone conversation in November 1968 and tried to assure him that he supported Johnson’s efforts to bring South Vietnam to a Paris peace conference with North Vietnam. He said he would do whatever Johnson wanted him to do to help before or after the election.

“I just wanted you to know that I feel very, very strongly about this,” Nixon said. “We’ve got to get them to Paris, or we can’t have a peace.”