I’m not too sold on the 1938/Hitler analogy myself.
Plus, were a new Cold War dichotomy to arise, I don’t necessarily see America holding the same moral authority. With American government devolving into a rather lawless, third-world statism, and American culture descending into a mix of socialism, dope, homosex and all-around depravity, it makes for a somewhat different dynamic.
I think the biggest dynamic is the fact that Obama has completely alienated the military. I don't see a dispirited military going all in to follow a dishonest, disrespectful, commander in chief that stands for the opposite of what the military represents.
You forgot the threat of national bankruptcy when the Petro-dollar falls. That would be an interesting reversal of roles. (Define irony)