In 1968, the Nixon campaign was concerned that President Johnson would make progress before the election at the Paris peace talks to negotiate an end to the war in Viet Nam. The Nixon campaign reportedly tried to stall any progress by convincing the South VietNam government not to join the peace negotiations as they would get a better deal from a Nixon administration.
There is one very important difference. South Vietnam was an ally of they United States. The Soviet Union was the putative enemy of the United States. Also incumbent DemocRAT president was trying to undermine (backstab) an ally to help the DemocRAT Vice-President and presidental candidate Hubert Humphrey, while the Republican presidential candidate was promising to help an ally.
In 1984 the former DemocRAT president was trying to enlist the help of the number one enemy of they United States to try to defeat the sitting President of the United States. If that had occurred during wartime it would have been treason.
Basically true, but the actions of the Nixon campaign certainly did not help the thousands of US troops that died due to the stalling of peace negotiations.
Also, doesn't it violate the Logan Act for private individuals to negotiate with a foreign government?