I have yet to hear a single principled left-wing argument against what these people did. And no "but paultards like them!" isn't a valid argument - nor is "but they harmed Obama's image!". Some people here are either machiavellians or utter hypocrites.
Its not about left or right... this is far more complicated than that (and I worry when people assume there should always be a distinct left and right wing response to everything). I don't think they did an objectively brave or noble thing, there's nobility in the idea... I know I keep coming back to this, but Manning could not have read all of those documents therefore he didn't know nor care about the consequences of their release. Snowden is a different case, there's a lot more sophistication and consideration in his actions.
I expect the government to do things I don't know about - my only real concern about this is whether their actions were legal and administered properly.