Failure of the United States ARTILLERY, or Snipers killing Adolph Hitler, in WWI led directly resulted in the rise of the Nazis and then the initiation of WWII.
If the Nazis didn’t take over Germany, then the Communists would have.
There would have been war either way. The only question is who would have started it, Germany or the Soviet Union.
Again, if we had maintained strict neutrality Hitler would have been stationed farther forward in WWI and he’d taken a direct hit by a French artillery shell.