He did not go to prison. The FBI and courts claimed Ayers did not serve time due to some technicality.
It was for questionable 'wiretaps'.
Same thing Blago is fighting against.
Same thing all the DEMS want to be made totally illegal.
Which is why they hated President Bush and his administration.
They don't like the idea that they could be 'caught' for what they are doing behind closed doors.