One of the reasons it's a bit difficult to get indignant about the WikiLeaks revelations is that what WikiLeaks did to the State Department is just what the State Department does to everybody else all the time, as WikiLeaks reminds us. Thus, we hear information secretly passed on to the State Department by informants in, say, Germany. Someone in Germany betrayed a tacit or explicit commitment to secrecy in order to inform the State Department, whether from pique, or a conviction that the world was better off with the Americans in the know, or because the Americans had corrupted him somehow, blackmail or bribes or whatever. (The last case is morally the worst; I'm not sure if it actually happened that way in Germany, though it probably happened that way somewhere.) Well, that's just what Julian Assange did to Bradley Manning. And if the State Department punishes Bradley Manning, well, if they were consistent they would punish their own informants in the same way.
We may regard ordinary government secrecy and espionage as morally dubious, but we usually don't condemn too strongly the people who participate in it, because we know they have a belief, and a plausible belief, that their activities are good for the world. Well, Julian Assange believes that government secrecy is bad for the world, and that in exposing government secrets he is doing a service to mankind, and this belief, too, is quite plausible. Indeed, in this case it seesm as if he benefited the target of his expose, the United States. WikiLeaks helps to dispel conspiracy theories by showing what the State Department really does. It's particularly useful to have some of the frank things the State Department says about bad foreign regimes exposed without the State Department's consent, because that means they can't get blame us for saying it, but they still get the bad press.
Wow-- imagine if WikiLeaks could leak the secrets of the Russian government! What a snakepit that would expose!