How long the US military would last in a war against the rest of the world
What would happen if the U.S. found itself facing off against the rest of the world? Not just its traditional rivals, but what if it had to fight off its allies like the United Kingdom, France, and South Korea as well?
In short, America would stomp them. Especially if it pulled back to the continental U.S. and made its stand there.
First, the U.S. has the world's largest Navy, by a lot. With ships displacing 3,415,893 tons, the mass of the U.S. Navy is larger than the next 8 largest navies combined. And the American ships, as a whole, are more technologically advanced than those of other countries. For instance, only America and France field nuclear-powered aircraft carriers. France has just one while America has 10 with an 11th on the way.*
And that's before the U.S. Coast Guard gets into the mix. While the Coast Guard isn't an expeditionary force, it could use its C-130s and other sensor platforms to give the Navy more eyes across the battlespace. It's counterterrorism operators could protect government leaders and secure American ports.
So attacking America across the water is a horrible idea. (Got that North Korea and China?)
Second, America's air power is the strongest in the world. Currently, it has approximately 14,000 planes and helicopters spread across the five services. That's more aircraft than the next 7 countries combined.
The world's only operational fifth-generation fighter, the F-22, would conduct constant air patrols across the land borders of the U.S. to prevent any incursion by enemy bombers. The Army's Patriot missile launchers would help stop enemy jets or missiles and Stinger/Avenger missile crews would shoot down any low-flying planes or helicopters.
So the rest of the world's militaries have to fight their way across a land border with the U.S. while their air support is falling in flames around them.
Guess what happens next?
The Army and Marine Corps' almost 9,000 tanks would team up with thousands of Stryker Anti-Tank Guided Missile vehicles, Apache and Cobra helicopters, and anti-tank missile teams carrying Javelins and TOW missiles to annihilate enemy armor.
The world's most advanced tanks, like the Leopard or the Merkava, would be tough nuts to crack. Artillery, aircraft, and anti-tank infantry would have to work together to bring these down. But most tanks worldwide are older U.S. and Soviet tanks like the Patton or the T-72 that would fall quickly to missile teams or Abrams firing from behind cover.
The other combat troops trying to make their way through the shattered remains of their air support and the burning hulks that were once their tanks would find themselves facing the most technologically advanced troops in the world.
Chances are, even infantry from France, Britain, or Russia would have trouble pushing through the lines in these conditions. But even if they did, the Marines and 101st Airborne Division would be able to swoop in on helicopters and Ospreys while the 82nd Airborne Division could drop thousands of reinforcements from planes to close any openings.
And all of this is before America becomes desperate enough to launch any nuclear weapons. If the enemy actually did make it through, they'd face nuclear strikes every time they massed outside of a city. And their forces still trying to reach the border would be easy pickings.
Minuteman III missiles are designed to strike targets far from American shores but they could annihilate an advancing army moving from Houston to Dallas just as easily. Navy Trident missiles could be fired from submarines in the Gulf of Mexico to destroy units waiting for their turn to attack at the border. Northern Mexico and southern Canada would become irradiated zones.
So don't worry America, you are already behind one hell of an impenetrable wall.