Some say he should have followed the procedures set out for "whistleblowers", but, I think it's fair to say those avenues are not really adequate or safe. So, under such circumstances, where one feels the need to correct or expose a perceived wrong doing, but feels the system will react like some kind of venus fly trap, what should you do, take the risk and maybe become a disappeared person ( Etc.) Do nothing and pretend nothing is wrong, or do what Snowden did ( obviously C.Mannings way was a disaster for him).
Sure, the law is the law, but we all know that there are good reasons to break laws, and sometimes breaking the law is the most ethical and moral thing to do, and in fact needs to be done. Governments make laws, some are good and right, but not all, and some are made to protect governments from being found out, these laws are abuses of power.
Snowden revealed what needed to be revealed, without him the government would have gotten more and more out of control. All the things we fought and died for for the last couple of hundred years would have gone out the window, what is the use of having words such as freedom, privacy, pursuit of happiness Etc Etc. if they are just words, just a belief but not a reality, no amount of security is worth such a loss.
Sure, we probably lost some advantages in "intelligence" but that loss just may prevent the loss of things that are much harder to get back, and if we lose those things, then our enemies have won, those enemies cannot defeat us with a thousand 9/11s, but if we lose our liberty, our right to privacy, our way of life, then we lose everything.