In 1948, the US Navy ordered an 80,000-ton "supercarrier" called USS
United States (
https://en.wikipedia.org/wiki/USS_United_States_(CVA-58). She was supposed to give the Navy its big leap into atomic arms. BUT, after James Forestall was forced to resign, the new SECDEF Louis A. Johnson, ordered by Truman to cut military spending, cancelled the carrier after her keel had been laid in favor of the Air Force's strategic bombers, particularly the B-36 Peacemaker. This leads to the legendary "Revolt of the Admirals" where a number of high-ranking US Navy admirals publicly disagreed with Truman and Johnson over their decisions, leading to Congressional hearings.
Now I'm asking, under what circumstances could the
United States have NOT been cancelled, maybe Forestall never meets with Dewey (which indirectly leads to his firing) or Truman selects someone other than Johnson or a scandal breaks about the B-36 and its capacities (the Air Force advertised the B-36 as having a lot of capabilities that it really didn't).
And more importantly, what would the Navy have looked like if the
United States-class was built in its entirety? Would the Fleet Ballistic Missile Submarines and Polaris have evolved if the Navy already had an established nuclear striking arm? How would carrier development have changed? The OTL
Forestall-class was more an evolution of the
Midway-class and only three-quarters the size of the proposed
United States.