Manning should rot in jail. What they did was far worse than Snowden, and certainly worse than say the Pentagon Papers leak (and yes I know the Pentagon Papers leaker himself stood up for Manning). Using the Pentagon Papers as an example, they proved that the US government was *lying* to the citizenry. And not for a "good" reason either. That's a big deal, and that's when a leak is justified. Snowden drew attention to what is potentially a major breach of civil liberties... and overhyped parts of it with Greenwald, and is apparently still carrying around a drive of classified data he doesn't want to release but wants to let people know he has for blackmail purposes (look, just delete it, okay), but the general point is that there's some justification here depending on the details of PRISM.
What Manning did was the equivalent of posting the US foreign service's instant messenger / Facebook posts publicly. It turned out that the US government was *not* lying about its claims! Oh boy! There was absolutely nothing new from a policy perspective in Manning's leak. I mean, perhaps you can take the position of "the US should have implemented a crash immediate withdrawal from Afghanistan" and use the various bad incident leaks to support your case... but.... again, this isn't news. We *know* there are helicopter raids & drone attacks going, and yes in a war there will be "collateral damage" (=civilian casualties), although of course abandoning towns to the Taliban leads to a different kind of civilian casualties. So the main effect of the leak was to take various honest assessments of the situations in various countries, meant for internal reading, and let the subjects being assessed read it. Great, way to discourage honest and useful reporting from our Foreign Service, exactly what we pay them for. (This is ignoring the disputed issue of if American operatives / informants were compromised.) Furthermore, both sides of a negotiation (say, Egypt / Israel or Saudi Arabia / Iraq) could now see what we told the other side, and surprise surprise, we told slightly different things to both sides.... in an attempt to make a deal and do diplomacy. Oh noes. (If we told one side which wanted 1 that we supported 3, and the side which wanted 9 that we supported 7, in the hopes we could eventually get them both to agree on 5.) I believe in diplomacy and believe that careful use of diplomacy - which yes, involves massaging egos and making people feel important and the occasional foreign aid bribe - will save and has saved millions of lives. Manning, by making diplomacy less effective, is a monster with blood on their hands, just not the obvious kind.
Of course, there's an entirely different issue in WTF was a private doing with access to all of the State Department's cables, and hopefully heads are rolling in information security, since there's just no possible way to vet every single enlisted man, this should have been State Department + relevant officers only.