Their complaint is that Russia is ignoring international law in not returning one who has been indicted for some alleged crime.
That trashdiction in Washington now would appeal to the same body of law which they ignore every day. Not to mention that if that band of pigs in Washington get their hands on Snowden, they'll just run him over or slit his throat, just like the FBI slit the throat of that Tsarnaev kid or whatever his name was.
To permit a United States employee to touch you is a death sentence. That is how far that non-jurisdiction has fallen. No nation would feel obligated by any interpretation of international law to deliver even an accused jaywalker to that heap of garbage. He'd just wind up extrajudicially murdered.
Under international law, perhaps first comprehensively explicated by Vattel, nations among that family of nations are regarded as what are called "moral persons." A moral person is the collective expression of the individual natural persons comprising a nation, its behavior a direct equivalent to those natural persons' moral obligations to one another. No stealing. No aggression. These moral persons interact with other moral persons in that family of nations, their behavior codified into a body of law called international law, or the law of nations.
The United States routinely ignores international law. It caused to be forced down the Bolivian president's jet on the suspicion that Snowden was aboard. The United States routinely commits acts of war with its drone strikes on sovereign nations, economic blockades, and no-fly zones.
In that family of nations, the benefits of whose body of governing law the United States would claim, the United States in no way resembles a moral person. It more closely resembles the town rapist or the town psychopath.
The United States "government" in no way possesses a moral claim to the benefits of international law. That jurisdiction is not a moral person. It is a band of pigs. Big difference.
