How would the Pacific war be different if the USA still used San Diego as its HQ in '41?
Pearl would see a build up of defences, but not the transfer of HQ and capital ships.
The USA still places embargo on supplies for Japan.
Japan still goes ahead with invasions of SE Asia and Philipines. Still successful.
Does the US navy enact strategy of a rolling reinforcement of the Philipines? Ultimately, Japan is still screwed, but how does the naval war proceed?