Traditionally, most military-what-if's are about Lost Causes, ie. Nazis with better gear, UK without Sandystorm etc. But how about other way around?
AHC: Create the smallest USN the US can live with during the Cold War. The USN must be able to do the following:
1.) Support the nuclear strike role of USAF and form the mainstay of secondary strike capabilities
2.) Support a limited war where land-based air is not available
3.) Support a corps-scale landing operation in a limited war
4.) Secure supply lines to a limited war situation
5.) Have ability to present visible power (ie. surface ships) to three global crisis areas at a time (In practice Northern Norway, Eastern Med and off Kamchatka in pre-general war buildup)
Securing SLOC's in a general war could be left out in a WWIII Battle of Atlantic rematch is futile, IMHO, as any General War would be filled with mushrooms and thus irrelevant.
So, with how small USN could US live with?