One thing you could do to try to get a better sense of this case is to look at historical "whistleblowers" and the short- and long-term outcomes of those. That is, look at cases where the media, the government, etc., label a citizen in that way, when that citizen takes it upon themselves to defy protocol, steal, or release information. This is not, by the way, the same as treason/spying, though it might be that in some cases the outcomes are similar (you'd have to look at the cases to figure that out).
Here's a start:
http://en.wikipedia.org/wiki/List_of_whistleblowers
Most famously, perhaps, you get Watergate and the Pentagon Papers. But also Serpico! (Of course, the latter is not National/the former are not International in scope... but the question is still the same: does an individual's moral intent in defying authority to release previously classified/secret/otherwise hidden information publicly have a tendency to end up better or worse for a group of people whom authorities have claimed such defiance would be bad/dangerous/etc?)
True, those are cherry-picked, and we might want to say that individual cases are not always comparable (if comparable at all). But if the question is: do well-meaning intentions, which lead to a defiance of authority, more often than not lead to more harm than good? Then we could simply count up the documented cases and decide that way, or, determine what criteria made some cases turn out positively, and then try to determine if Snowden's case fits that.
I honestly don't have an answer or clear opinion, but given the above, I don't think it's impossible that this case could end up being a good thing in the end.
to yet another topic of discussion.
