But you wont get Washington.
For one, there’s already units in the US, all of which can be in DC if need be. There’s the British in Canada. British ships to block the way, American ships to prevent the landing from ever happening too. (6 Aircraft already on hand, what’s it cost to put 3 carriers in the water to add all those fighters too? 48 IPC? Leaving what, 22 IPC? Another 2 fighters for scrambing!)
You will have the effect of pulling all the Americans out of the Pacific for a round, however. If that is your goal.
True, it could be prevented, bringing your turn 4 fleet to sz 89 (G.O.Mexico) which puts it 2 turns from Hawaii, or the W. Coast, with those carriers in the East coast, I just prevented a build in the west coast. Those carriers will be 2 turns from Hawaii if they go that way. Seems like it would be a major disruption for a planned USA Pacific first approach, buy Japan 2 additional worry free turns, and even permit the sacking of Either India or Australia before the US could thwart them.
All this by simply sliding a few boats already in the water to another spot in the water. True, It would buy Russia 2 turns as well as my transports would be out of position…but given that Pacific first is your favored approach, taking your attention from the Pacific seems warranted.