I do not know much about the United States military of today except that given its air capabilities it should be able to handily defeat whatever the Legion threw at it. In your opinion how quickly would our current military destroy the Legion?

Truthfully? It would be comparable to http://en.wikipedia.org/wiki/Battle_of_Omdurman.

That is to say, the Legion would be massacred, sure in close combat they might get a few kills, about three, because the American Military would probably just call in a few airstrikes and then waltz in with the Tanks.

EDIT: As for how fast, it would take the US military probably a few days to group its forces, so around One-two months.

You're putting a pre-apoc army decked out with the latest toys against a post-apoc army made of primarily meat with lawnmower blades lashed to pieces of wood?

Whadya think will happen?

If you read the topic you would see that I did not ask if the Legion would win. I asked how long would it take for the Legion to lose. Before you ask sarcastic questions to derail a thread, how about you read what the thread is about first?

Very quickly. Legion may have strong troops but the United States SCIENCE, has drones, carriers, and very strong infantry/armor capabilities.

Depends on the situation. Is the US military magically transported to the Fallout world, or the Legion transported to ours? Does the US military have an infrastructure to support it? Does the Legion? What's the political climate? What is the reason for the war? Do other governments take issue with the war? Where is this war being fought? How long have they been aware of each other? Have the Frumentarri infiltrated US ranks?

The United States military in its toatlly and current geographic positions are transported to the Fallout world with the infrastructure available in said world. If you have ever read that reddit thread were the military is transported to ancient Rome then its a situation like that only with the Legion instead I suppose.

http://en.wikipedia.org/wiki/Rome_Sweet_Rome

Rome, Sweet Rome is what I'm basing this situation off of basically.