Assuming that the US & Japan never come to blows but that the US enters WWII in Europe (say, no later than the end of 1942), what do you envisage the US Navy's build program to look like? There were a lot of fleet carriers built (and planned) for the Pacific but I don't know if that would have been the case if the Atlantic was the major theater of operations. What would have been built instead? More DD's? Escort carriers? Cruisers? BB's? Maybe even the Montana class a little early (no Panama canal to restrict transit)? Where would subs fit into the fleet? Would the additional shipbuilding capacity have gone, instead, all to merchant ships and/or landing craft?
Assume, for any speculations, that the Pacific Fleet at Pearl Harbor remains intact. Japan is sufficiently bogged down in China (and maybe with the Soviet Union) that Washington sees it as a potential but not immediate threat-i.e., there is no need to weaken our Pacific Fleet but no immediate need to augment it, either (except, perhaps, with Atlantic Fleet ships that have been supplanted by newer units).
What kind of US Navy do we see by V-E Day?