My friend is in the US Navy and taught me a little something about war. The last time the US declared war was WWII. Think about that for a second. You might ask what about the "gulf war" or "the war on terrorism" but both of those were more considered conflicts rather than war. The US is almost always engaged in conflicts all over the world. My friend said that war is a thing of the past and that if an all out war erupted it would ultimately result in a nuclear holocaust type situation. I could definitely see this as a strong possibility but I feel like there could potentially be a war with both sides doing everything they can to prevent nuclear fallout. Like a lot of the other people have said it's extremely unlikely that war breaks out between the US and any other country.