The article linked above lays out the argument that Edward Snowden was simply a brilliant spy—including brilliance at public relations. Here is the key passage:
Mr. Snowden’s critics regard the whistleblowing narrative as at best incomplete, at worst fodder for the naïve. They do not believe that it explains the unprecedented size and complexity of the penetration of NSA files and records. For one thing, many of his critics have intelligence clearance. They have been privy to the results of an NSA investigation that established the chronology of the copying of 1.7 million documents that were stolen from the Signals Intelligence Center in Hawaii. The documents were taken from at least 24 supersecret compartments that stored them on computers, each of which required a password that a perpetrator had to steal or borrow, or forge an encryption key to bypass.
Once Mr. Snowden breached security at the Hawaii facility, in mid-April of 2013, he planted robotic programs called “spiders” to “scrape” specifically targeted documents. According to Gen. Dempsey, “The vast majority of those [stolen documents] were related to our military capabilities, operations, tactics, techniques and procedures.”
I must confess that my relevant expertise for judging such an argument is limited to what I have learned from TV series that attempt to portray semi-realistic spywork, such as Burn Notice, Sherlock and Elementary. (The adjective “semi-reliastic” is meant to contrast these shows with others like Alias or Chuck that intentionally portray fantastical spy work.) What Edward did would certainly have made a good plot line.
For my take on the policy issues raised by Edward Snowden’s revelations, see my column “The Government and the Mob.”
Update: I got some pushback on this post. See the discussion in the storified tweets “Edward J. Epstein, Miles Kimball, Brad Delong, Alex Bowles and Ramez Naam: Was Edward Snowden a Spy?” Ramez Naam in particular has good arguments against the idea that Edward Snowden was a spy employed by a foreign government.