"Can't" here should be read in the same sense as "he hasn't crossed our border" (Russia) and "the extradition request wasn't filled out properly." (Hong Kong/Ch

"Can't" here should be read in the same sense as "he hasn't crossed our border" (Russia) and "the extradition request wasn't filled out properly." (Hong Kong/China) Since this is an espionage case, there is really nothing about the crime offensive to Russia or China, and these countries really don't want to seem subservient to the United States. At the same time they don't want to damage their relationship with the United States, so they keep trying to punt on the issue by not arresting him but not letting him stay put, hence the creative use of words. Snowden is probably in good shape. If he can't leave Russia for one reason or another, that may change the moment Russia wants someone accused of a crime in Russia sent back to them from the United States, which I understand happens. In that case they probably won't be getting anyone unless they swap for Snowden.