I'm persuaded that LBJ escalated our involvement in Vietnam because he thought that was required to play "RISK" in Southeast Asia in order to get the "GREAT SOCIETY" passed in Congress. He thought he could parlay with the VC and the commies in North Vietnam. Besides being fooled by those commies, LBJ was unable to appreciate the geographical difference between fighting a war on the Korean Peninsula, and a war in Vietnam with the "Ho Chi Minh Trail" going through Laos and Cambodia.
Check out Presidential Historian Michael Beschloss. Here's a link.
I believe LBJ used the months and years after Nov 22, 1963 to escalate the conflict in Vietnam and to push Civil Rights legislation so Americans wouldn't 'look behind the curtain' to see what was to become the Warren Commission Report.