Alasdair Czyrnyj said:Sorta what Germany did in the book 1901.
On invading the United States in the post-1950's world, I think that the main problems are the American navy, air force, and nuclear arsenal. The navy and air force can be dealt with: just set up several nasty insurrections in countries vital to US interests, and wait for the realignment of forces. As for the nukes, the best I can come up with is a surprise first-strike, but I don't know how much warning time the Americans would have, and if they could fire stuff off before they're hit. Of course, the opposing country could get really lucky and acquire the missile codes, but that would be near-ASBish in terms of luck.
The only way I see around that is a TL a bit like "Red Alert", no Adolf and a far more agressive USSR (Probably with Trotzky at the helm) The Red Army overruns Western Europe in 1940 and forces Great Britain into a Finland-like status.
That derpives the US of a lot of the scientists they needed to get both the Manhatten Project as well as the ICBM`s build.
Lets say the US gets the nuke anyway, but relies on strategic bombers and Carriers to deliver them. In such a situation the USSR could get the idea that this is the last chance to deliver socialism to all the needy. A couple nuclear tipped 25inch torps (the November-class subs were originally planned around such a monster) take care of a large part of the US fleet. From here it gets interesting.