You must not know much about Americas power or defense if you think a country could simply "launch some nuclear missles at us"... No country could successfully launch a nuclear missle that would hit anywhere on US soil, it would be shot down over the ocean... The only way for a foreign country to use nuclear weapons against us would be for them to sneak it in to the country somehow, then detonate it, and then, their fucked... We got mad nukes and shit.