American Intervention tipped the scales toward the British and allowed the Allies to impose the Treaty of Versailles on Germany, crushing their economy, and creating the conditions for dictatorship. Americans also financially supported Bolshevism as a counterbalance against the powers of central europe, unleashing that dog on the world.
Here is a great book on the subject.
http://www.amazon.com/Wilsons-War-Woodrow-Blunder-Hitler/dp/1400082366
Where did you all learn your history? Government school?
At any rate, here's more satire that Bill might appreciate. World War Two is the Democrats fault!
You are not serious?
The war would have dragged on, eventually the dust would have settled, the axis would have been crushed, because you can't wage war against all of the known world.