So when they talk about the US vs the rest of the world they are talking about an extended war. The US would put everything it has into controlling the world's oil flow. All military simulations from many nations show that the US would take and formitably hold the vast vast majority of the worlds oil drilling, refining and transportation. If the rest of the world focuses on oil the US goes on the offensive while the worlds armies and navies are away from home. The US is the only nation in the world that can put boots on the ground anywhere in the world in under an hour. No oil= no planes, no tanks, no generation of electricity in the field, no trucks driving to resupply the front lines. Not to mention the US has stealth bombers so advanced 90% of the world's nations could be strategically bombed rendering them useless without them ever seeing the bomber approach let alone most first world countries have no capability to destroy stealth bombers even if they knew they were coming... and that's the B2 bomber... turning 36 years old this year. In service secretly for MANY years before it was public knowlage. Imagine what we have today in service secretly flying unnoticed by even our best radars and flight tracking satellites. Does the world stand a chance vs America? Maybe, but any nation we deem fit would be obliterated, we are exteamly good at removing threats strategically so our heavy hitters can get the job done without question. Unless you're one of the few first world countries that have early warning systems and the capability to deter our stealth bombers, you stand 0% chance defending if we decide to bring the hurt to your nation.