NSA chief: Snowden ‘betrayed the trust and confidence’ of the US

He certainly betrayed the trust and confidence of certain people and entities in the executive branch of the US government, that's not in dispute.

But it is morally obligatory to betray trust when you are trusted to do a thing which is itself morally indefensible. Whether Snowden betrayed a trust is not at issue, the moral (and, subordinate to that, legal) character of the subject matter of that trust is at issue.

No, US did that to itself. Snowden just let everyone know what the US government was doing in their name.