Sure seems like a lot of speculation about Democratic politics of the time, would a veep go to war against his president fighting an issue they both wanted, seems like a lot of unnecessary searching for something just to protect the never ending myth making of one of the sleaziest American presidents of all time.
Not working hard for the president is not going go war with him.
The Democrat party of the 60s is nothing like the party of today.
It was not nearly as disciplined as the party today.
Southern Democrats were often at odds with the Northern Democrats.
The Civil Rights act was only just barely passed and only because Republicans voted for it.
Without LBJ twisting arms it would not likely have passed.
What I am saying is if LBJ did not really work for it, it may not have passed, if he was not president he may not have.
His animosity with the Kennedys may have made him less enthusiastic. It is also well known that JFK did not like LBJ.
LBJ was well known for being a prick and one who kept grudges.