Snowden and Manning broke the oaths they took.
Assange is guilty of espionage.
> but Assange isn't American, not US permanent resident, and he has no duty to be loyal to the US.
That's besides the point, for example if a CIA agent is in China gathering intelligence on classified things, he is clearly guilty of espionage. You don't have to be a citizen or a permanent resident or have a duty to be loyal to a country to be spy.
edit: typo