Doug, the important thing to understand is that the only thing that socialists can demand is public ownership of corporations. If the US went socialist, then the question of how property can be socialised on a global scale becomes elementary. What inhibited socialist development in the past is that weak and isolated countries like the USSR in its infancy, or Cuba today, simply lacked the leverage or the means to exist in a capitalist-dominated world.
However, these sorts of problems seem entirely secondary to the ones we face in our capitalist future. As I have pointed out repeatedly to fans of "market socialism" or the Albert-Hahnel schema, socialist revolution will not be inspired by some kind of air-tight, logically and morally consistent blueprint but because the everyday conditions of life are intolerable.
The goal of Marxists is not to supply blueprints for the future but figure out ways to break down illusions in the capitalist system and organizing people in struggle against it.
Louis Proyect
(http://www.panix.com/~lnp3/marxism.html)