Take your standard (and admittedly cliche and very unlikely) "Nazis win the war" (USSR defeated, UK bows out after a disaster at Dunkirk, USA never gets involved variant). The Nazis manage to push all the way to the Urals and stop there.
Let's set aside arguments about how plausible any of that is (I know it's not very) and accept it as the scenario axioms, please.
Anyway, down the road a bit, the USA gets more active in defense of the rump-USSR and begins to station forces along the Ural border. With everything having to come from the Pacific or up from Iran through Central Asia, how large an American (and UK, Australian, etc) army could likely be maintained in and just east of the Urals?
Let's set aside arguments about how plausible any of that is (I know it's not very) and accept it as the scenario axioms, please.
Anyway, down the road a bit, the USA gets more active in defense of the rump-USSR and begins to station forces along the Ural border. With everything having to come from the Pacific or up from Iran through Central Asia, how large an American (and UK, Australian, etc) army could likely be maintained in and just east of the Urals?