Are you asserting that Snowden was explicitly working as a Russian agent in order to weaken / embarrass the US intelligence agencies?

While I believe he probably caused more harm to the US than help, I really don't believe he is / was a Russian agent.

Seems like Russia simply ended up with him due to travel restrictions, and since they have absolutely no reason to turn him over to the US as that might discourage future and actual collaborators, they allowed him to remain. A