The trouble is that in most of the recent prominent government "whistleblowing" cases (Snowden, Manning, the other one I forget) there's a great deal of disagreement on the legality of what has been exposed. The issue is that an individual sets himself up as judge and jury on the subject of complicated legal matters which he might not fully understand.

I will say that both Snowden and Manning went well into the territory of leaking stuff that wasn't illegal in addition to stuff that was at least debatable.