JFK killed during PT109 incident Aug 1943

How would hist have been affected had JFK, while skippering PT109 off the Solomon Islands in Aug 1943, been killed ?

With Two of his sons Dead in the War Kennedy Senior would have abandoned politics.

Having Sacraficed Two Sons to the War Kennedy Senior would have pushed his two Remaining Sons even Harder into Politics.
Absent Kennedy would Johnson have won the Democrat nomination and the election of 1960. If Johnson were not the candidate might Stevenson have lost a 3rd election.

Would Nixon or Johnson have ended up blowing up the World in 1962.

Alternatively how would Nixon have dealt with Civil Rights issues. Might Johnson taking the kinds of positions he took in the later 60s earlier have had a big issue- him being a Southerner