1. If he applies for parole he is implicitly acknowledging that he was guilty of the crimes.
2. If he's paroled he would still have to live under the supervision of the Federal justice system and probably won't be able to travel outside the country. He may consider himself at risk in the U.S. if he's not in custody behind bars.
They didn't do it with the Walker spy ring and they won't do it with Pollard either