You could even do a house rule for that, such that 1-3 US destroyers would be able to cross ATL and join/protect UK/ally fleets during defensive combats on turns 1-4.
I am currently working on a house rule where one can do that with Lend-Lease that US can transfer equipment.
I am also trying to set up a different rule for declaration of war where you can declare war but if you don’t have just cause, then you take a penalty for attacking but if you have just cause, then of course you’re free to declare war.
I was going to changed the let up of all units, try to get it to reflect actual WWII in 1940, for example USSR will actually have a Pacific Fleet as an example.
I was going to something crazy like put in merchant ships for Lend-Lease that will make convoy zones more useful and for pain in the A$$ to disrupted. So I had an idea setting up fighter units closer to real numbers ( I am making this number up to make an example) Let’s say I put ten fighters on London, I was going to make one of them a US fighter to represent Eagle Squadron, US will be neutral however because Eagle Squadron is in London, this is a “just cause point” for Germany and Italy to go to war with US.
I have other examples but this makes the point.