Assuming we'll send the supplies to the Soviets but Hitler won't dare to attack Britain and USA.
But that move would probably provoke Hitler into declaring war.
Certainly, in a similar fashion as happened in our timeline. I mean the entry of America into the conflict.
Hitler had to make the same experience as the Sun King of France, and later Napoleon: for a while, you can bully and coerce your neighbor nations at your pleasure if you’re strong enough- but after a while, they will all form an alliance against you.