If every nation in the world allied and invaded the United States, would they succeed?

the lost logical answer is no !

America would destroy all of the world armies several times over. If it came to a war of that nature a world threat to the Homeland!
Americans would rise and join in droves and a draft would be put in place.
well placed nukes on well populated cities to cause mass death and target of civilian population.
Invasion of the American homeland can't be achieved as the civilians would rise against and fight back and the guns already at the ready

Non-professional, layman's, non-assertive opinion:

Any war with the U.S. will always be a matter of sheer numbers vs. technological and tactical multipliers. And then it depends on your definition of "victory." I mean, if we leave unconventional warfare off the table and assume absolute non-interference by any other states (or support by other states exclusively against the U.S.,) China could, IN THEORY, in a war of unprecedented attrition, in which they would lose millions of lives, stage a slow, painful, disastrous invasion via the arctic and Canada. That would never happen, though, because the economic and human costs would set the whole world back decades or centuries.

If we're talking about full spectrum, combined arms warfare against the U.S. - could the WHOLE WORLD defeat the U.S. military? Almost certainly. I mean, a combined Russian and European campaign of air strikes against the U.S. staged from Britain and Canada Japan, Alaska (once secured,) and numerous islands and air bases, as well as a Chinese and Japanese effort in the Pacific, would force us to fight in two theaters (something we're no longer optimized to do) against overwhelming numbers of enemy vehicles, soldiers, and munitions. Barring the use of nuclear or biological weapons, it would still be a terrible war of attrition, though. The speed, efficiency, and more importantly, experience of U.S. forces from decades spent engaged in leading edge combat around the world would mean a long, grueling campaign in which the attackers would lose a great deal regardless of eventual victory.

Then they'd have to contend with an armed, fanatical, bitterly entrenched domestic insurgency combining remnants of the armed forces, average citizens, first responders, police, etc. etc. Probably for decades... or longer. Pacifying the U.S. would likely become untenable, and eventually some sort of new independent government would have to be allowed to form simply because the costs of the quagmire would be too high for the world to bear, given the decimation of the global economy which would ensue following the collapse of the United States economy.

If nuclear weapons are on the table... then it's the end of the world as we know it, period. The world could "win," but it would be absolutely disastrous. We have first and second strike capability, and even with preemptive crippling of some of our nuclear capability... we would still drag the rest of the world down into hell with us, inescapably.

In short... could the U.S. fall to a combined international coalition of advanced military forces from, say, Russia, China, Japan, Canada, and Europe? Yes. Would the victory taste as bitter as defeat though, for all of humanity? Absolutely. This is why the U.S. is perceived as the world's sole "hyper" power today. For better or worse. And it's unlikely the resulting insurgency could ever be pacified.

Peace.

a reply to: nito92

Yes they did.

No. The logistics of it simply makes it impossible when added to the military power of the US already. Most of the worlds forces would be of no use in such a fight. The US would grab Canada and Mexico and put in puppet governments. And the it comes to worlds lack of carriers. Even if the world could put together enough transports to move troops and then provide logistical support they would never get to land. They would have almost no air support and have to face the largest air force on Earth belonging to the the USAF and the second largest air force on Earth belonging to the US Navy. Against that would be only 1 real carrier from France. It would be a blood bath at sea.

On top of that you would need at least 10 to 1 numerical superiority to invade a well a high tech military like the US. The US with the NG and reserves is at 2.3 million just that means you would need a force of nearly 20 million. Those kinds of numbers do not exist. Of course a draft would be called although the number of volunteers would likely make it not needed. The US would have plenty of time to train new troops. So you could have 10 million troops waiting. Building just the landing craft needed to invade the US would take years.

However lets say the US has no nukes, no air force, and no navy and the World has magically gotten enough landing ships to give the world a fighting chance. Most of the worlds armies would be never be able to stand on a modern battle field much less and amphibious invasion. With such a wide range of weapons, ammo, training, languages, tactics, coordination anything would be impossible. Supply would be impossible.

The entire thing is an exercise in futility. The man power, ship power, air power, etc. simply does not exist to invade the US.

originally posted by: markosity1973
Think about this;

The world has about 7 billion people, America 319 million.

All America could and probably would, out of sheer evil spite, do is nuke the entire planet to ensure that nobody wins.

If everybody is dead hope will be dead too... just pack it in, swollow the defeat but live to fight an other day.

Is what I would sa

If it reached the point where the conventional forces were losing and a successful invasion looked likely, it would make sense for the nukes to fly. So no, no one is winning THAT war.

a reply to: nito92

If the U.S. Military Communication and civil communication satellite's are taken down then it wouldn't take long at all.

originally posted by: Misterlondon
Of course they would.. a handful of nations would be able to do it...

How? What nation can take on America's Navy? If you can't get past the Navy, you are worthless in an invasion of the US.

Those nations would have to invade Canada first, to use as a base, and start line, the logistics of an attack like that are just horrendous, plus everyone getting in each others way, there is just not enough specialised shipping to make it happen, or aircraft, look how long it took the allies to invade Europe in 1944, three years planning, three years construction of the means to invade, just what would be the point on invading the USA?

originally posted by: Indigent
a reply to: ketsuko

They are buying America piece by piece anyways

Good luck to them getting it back home. lol.

Anyway, all them black projects would come out.

The other countries will think they are fighting darth vader and the empire.

What do you think that cute robot mini shuttle was doing up there for a year?

Death Ray space platforms! Muhahahaha!!

a reply to: pikestaff

Those nations would have to invade Canada first

Er No.

The original thread title was " If every nation in the world allied and invaded the United States, would they succeed "

Canada would part part of the allied nations, so why would Canada have to be invaded ?

a reply to: burgerbuddy

Anyway, all them black projects would come out.

Do you mean " Mythical Black Projects "

Good piece of propaganda there. Let other nations think you have terrifying weapons which should scare them into ever starting a war.

The U.S. didn't even realise that Russian Submarines where parked near their coastline. So much for Hi-Tech surveillance.

People are so gullible.

originally posted by: NoCorruptionAllowed
An attack by the rest of the world upon the USA would only result in the death of the entire planet.
Nukes would definitely be used against attacker countries if we were being attacked by everyone. There is no way that nukes would not be used in such a scenario.
And everyone would lose.

That's why it's called MAD, mutually assured destruction !

Of this 7 billion number mentioned, my guess is that a quarter of them are only a couple meals away from starvation on any given day.

a reply to: alldaylong

Because a) they did know they were there and monitoring them and they would never say it and b) the technology they would use is dangerous to sea life and is not used constantly.

It's a logical fallacy. How do you invade the US with subs?

a reply to: OccamsRazor04

they did know they were there and monitoring them

No, they didn't actually.

freebeacon.com...

How do you invade the US with subs

Who mentioned that ?

Americanssss (generalisation) are not afraid of all the worlds armies, navies, air forces put together- even though they haven't been victorious at war for a generation

they are afraid of....

-terrorists

-their own governement

-their neighours

and they grasp with sweaty palms their gunssss and beat their hollow chests on internet chat sites

I sleep with no gun under my pillow and my front door unlocked and fear nothing. Such a shame a country which the world fell in love with at different stages throughout recent history is hunched in disparity and shame, shackled by paranoia and FEAR. Hence the almighty defence budget. haha DEFENCE budget now there's a wolf in sheeps skin.
Good luck America, if you don't find some medicine the rest of the world is the least of your problems....

non u.s&f.o detectable mentioned nations
insufficient analysis-
"melting pot" required

Agreed, but, they would surely use them all before starvation and they would give them enough food and / or water before.

a reply to: RadioRobert

Ummm, they could start gathering way before the war, with bases around key countries or at least all over the americas, with secret transport methods. It would be a slowly begining.