With classic rules lets say the SUB can be spared the first round and submerge or retreat to the US West coast
Submerge doesn't happen in classic. So we'll say the sub withdraws to the US West Coast.
if Japan does a Pearl lite attack. On US 1 you could then counter with 1 SUB, 1 Battleship, and 1 TRAN as fodder, to be reinforced with what ever else the US chose to buy (assuming navy due to the KJF).
The question is, if Japan did Pearl Lite, what is there to counter? Maybe nothing. See my earlier post about a US counter of 1 sub 1 trn 1 bb at Wake against a Japan fleet of 1 ac 2 fgt 2 bb. Disastrous for the US.