He is already a civilian and will not be court marshalled, which is why Bradley Manning is in a military prison. Ellsberg enjoyed the full rights of being a civilian when he leaked from RAND Corporation. The thing that a lot of people do not get is that the Snowden case would go through the civilian courts system. Sure the more sensitive subjects would be subject to injunctions and have be argued before being admitted to court, but the same thing is going to happen with the EFF case in the Northern District of California.