Nixon used his dirty tricks campaign on the guy that released the “Pentagon Papers”. The papers were a government analysis of JOHNSON’s running of the war. Nixon loved America.
Right before the gap in the tapes Nixon said something like “It will bring up the whole Cuban thing...”
Somehow bringing up the Bay of Pigs disaster which would bring that disgrace to light again? (IIRC, one or two of the guys involved were Cubans involved in that mission), or something worse - the use of the Cubans by the CIA/LBJ to assassinate JFK??
And then by resigning, he thought about fighting it, others told him to fight, but he thought it would be best for America to resign.