Countries with a big hammer will inevitably end up using it in ways that turn out to be stupid. (See: Iraq.) It also, inevitably means that the security umbrella of the world will be used in ways that the country that owns it likes. (See complaints by every country except the U.S., many of them justified.) But for all that, you can certainly imagine a country with an America-sized military advantage doing much worse things with it. Many worse things. In fact, when you think about alternative histories, we’re pretty far into the “happy” zone of the spectrum. Not all the way to utopia, mind you. But a lot better than you’d imagine, if you’d never heard of the United States of America and you were plotting out your science fiction novel with a dominant, heavily armed nation.