Situational can make it hard.  If I knew I had a fighting chance (say at least a 30% chance of a win, I would stick it out, but if the Japanese wanted to play a waiting game (so planes could be used elsewhere) and build up for the attack, this fight is not going to be much of a fight.  I guess like Russia, it comes down to just how long you can hold out.  So what is considered a victory for the allies?  If India can hold out till Round 9, do you consider that good for the Allies?  I know that goes hand in hand with holding Russia, but for the experts out there, how long can you hold out and still achieve Allied victory?