The United States is a rather disfavourable country in A&A Europe. A pain for Germany, and a boring position to play by yourself. However, there are ways to get in the game fairly quickly. I believe the U.S. has too much money, because it is very possible that they can use this money. The main point that I focus this on is the fact that Morocco is directly within transport range of mainland United States. Germany tends to forget this, and at any cost, the U.S. should attempt to move troops into Morocco.
There is a noticeable difference in the way the U.S. must be played- They MUST not concern themselves with losses. Everything is expendable. I recall playing as Germany and eating into the Soviet Union- And the U.S. could not do anything with their massive fleets because I had no ships for them to fight.
The point is Germany cannot afford to lose units, while the U.S. can. With ridiculous amounts of money to replace everything they’ve lost, it’s worth losing a fleet just to land a few tanks in Africa. This ensures the safety of the Middle East, and the conquering of Africa. Germany cannot afford to divert it’s attention to reclaim it. These landed forces can make a zip through the Middle East and aid the Soviet Union within a few turns.
In short, the United States must mobilize all it’s units immediately without worry about losses, and certainly without worrying about defense. As long as the U.S. is being played by an person with an IQ of 1 or more, I believe it’s impossible for Germany to invade them.