i believe everyones overlooking a bit of information here, motive.

why would the US government ever want to invade japan? its not like there would be much benifit of doing so really. sure youd be able to take over a few companies and add their income to the government through tax, but a couple billion dollars wouldnt be worth it to go to war that would cost at least that.

plus there would probably be a huge anti war movement from the US citizenships, and lockup the US economy if we did go to war for no good reason.