Re: Captain America 2: News and Speculation - Part 1
You ask why would the Soviets do that, when that question has already been addressed in the storyline the movie is going to be based upon.
In the comics, they took him back to Moscow because they thought he had the super-soldier serum. It turned out that he didn't, so they turned him into Winter Soldier for a myriad of reason.
In the movies, he has a version of the super-soldier serum, so the Soviets wouldn't be so eager to give him back.