We wouldn't have had they not thrown their lot in with Germany.
Mussolini and Hitler both acme to power in the post WWI era...when isolationist policies and non interventionist policies were popular in Europe as well as the U.S.
The whole of Europe saw what was going on in Germany and Spain and Italy in the 30's and sat on their colletive thumbs because "it's not our fight".
And look where that got Europe and eventually the U.S.
Our own non interventionist and isolationist policies in the face of what Japan was doing in the Pacific facilitated the attack on Pearl Harbor.
And even after 9/11 here we are again with people advicating for that same kind of failed foreign policy strategy yet again.
We clearly don't learn from our mistakes because we keep repeating them.