Von Braun is dead, and with no evidence to implicate him personally, I don't know where you'd go with this.

The Russians didn't get the all the scientists we did after the war, but it was not for lack of trying, and they DID get a lot of hardware. I suppose we could have stuck our noses in the air and left the scientists behind or hauled them back to the U.S., tried them as war criminals, and dumped them in prison or executed them.

Then maybe we would have been standing around scratching our butts when the first Soviet ICBMS started crossing the skies, and we would have wound up under a murderous dictatorship anyway.

The Cold War was based on the big picture of keeping a particular oppressive expansionist political system from pretty much eating the whole planet. To do this, America and its allies have done more than a few things that they would not be proud of under other circumstances, primarily IMO supporting small-time thugs in charge of countries that we did not want to see become Soviet satellites. Not sure bringing Von Braun and crew into America to keep us from falling behind in the missile race comes all that high on this list.