Pardoning him would create a pretty bad precedent for everyone else with a security clearance. How do you tell the next guy that dumps a stash of classified doc

Pardoning him would create a pretty bad precedent for everyone else with a security clearance. How do you tell the next guy that dumps a stash of classified documents in some journalist's lap that, no, that wasn't juicy enough to get a pardon, so he's going to jail? Despite the public interest in what Snowden revealed is, the position of the administration can only practically be that whatever you think about it, if it's classified, it's not up to you to decide that it should be public.