According to what I've read, Pollard simply deliverad information to Israel which was vital for Israeli security. Giving information to an ally without permission is a minor crime under US Law. Even if he was sure he did what is morally correct, he still plead guilty of violating US Law. Morality and Law not always go together. But the penalty for him would be four years in jail at worst, and the US gave him a life sentence!!!
And even if he really deserved a lafe sentecnce under US Law, Govts usually pardon offender in bilateral agreements. Israel released several terrorists who deserve life prison at least, jut to seek "peace". And it was endorsed by the US. Why cannot US president pardon him, and send him to Israel???