I don't know that there can be an objective criterion. Whistleblowers who succeed in getting public opinion on their side -- as I guess Daniel Ellsberg did, on balance, though there were certainly many who disagreed -- will get away with it. Those who don't, won't.

I'm not sure it can be any other way. The government has to protect itself, and for the most part, that's a good thing. The only authority that can set limits on that self-protection, to keep it from going against the public interest, is the public itself.

I too support pardoning Snowden. He risked his life and his future to bring us critically important information about the activities of our government, and he did so in as responsible a manner as I think he could have under the circumstances. This Guardian article certainly speaks to that point.