I don't fully agree regarding Manning. He revealed diplomatic cables, which was basically a work of U.S. diplomats, who have been writing "honest" assessments from inside those countries, under the condition that it remains secret. In my opinion, it was unfair to the U.S. gov that it was published - and I say this as a non-American. If leaking this should be automatically pardoned, we would first need a completely different model of how foreign diplomacy should work. (But I agree the life-time sentence is too harsh).

Snowden case is different. (I also don't like that those two guys are mentioned together).