And strategically, assassinating Snowden is about the worst possible move for a US linked agency since (i) it makes them look bad, even to some of the people who think Chelsea Manning got off lightly and (ii) it makes Snowden's revelations interesting to a whole bunch of people that don't read Hacker News and think that articles about email monitoring sound incredibly dull.

You don't have to believe that every US chain of command in every theatre of operations has qualms about "disappearing" people suspected of quietly leaking secrets to think that causing an international incident over a public figure like Snowden, even if the assassins were guaranteed to succeed and not perish in a firefight with Russian cops called by an FSB security detail, isn't going to do them any good.

I can't think of dozens of living whistleblowers who blew the whistle on the CIA or NSA, or both. Which group were you referring to?

There've been several just in the last few years, Ellsberg was a genuine whistleblower, the NSA wanted to stop the publication of Bramford's work. On top of that there have been multiple genuine, grade A, real spies. They get caught, tried, convicted and imprisoned - they don't end up dying in car accidents or even accidentally falling on a pair of scissors in prison.