Answer:
Treaty: If the French, who started the war, had stayed out of treaty negotiations, the US could have more easily pushed through there less punitive plan. Germany would not have faced unrealizable actions, and their economy would not have been destroyed.
LON: The US had no place in the League of Nations. LON was a European matter. Had the US joined, there would have been an unfair balance of power, BUT US involvement in WWII would have been near instantneous.
Europe felt the impact of America's slump through lack of capital, less products were being bought from Europe by Americans, American investors weren't as active, etc.
The original founding members of NATO( North Atlantic Treaty Organization) also known as north Atlantic alliance were
united state Netherland
Norway Iceland
Canada Porgual
France belgium
Italy Lexumbourg
United kingdom Denmark
The organisation was founded in April 1949