@pangloss, who knows? But what's certain is that, if we take your view, then we would have been relying on Hitler to exercise self-restraint... Not a risk worth taking, in my book.
However, I completely agree with your earlier suggestion that we as Americans are indebted for our freedoms to the soldiers from other countries. Again using WWII as an example, the sacrifices of British, French, Canada, Australian, and, yes, Soviet soldiers all come to mind. Defeating the Axis powers was a group effort.
This insight is the reverse of the argument we often hear that "France owes us their freedoms." In fact, in many ways, we as Americans owe the French our freedoms, not only because of their contributions in WWII but also, importantly, their vital assistance in the American Revolution and various other points in our history.