Seamless and as darkly riveting as any John le Carré or Graham Greene thriller, Laura PoitrasCitizenfour puts an indelibly human face on NSA whistleblower Edward Snowden, while ripping away any mask of pretense that the most massive and sophisticated breach of privacy in American history had grounding in reality, let alone the law.

Screen Shot 2014-10-11 at 12.12.01 PMAlmost defiantly avoiding most of the technological gimcrackery we’ve come to expect in advocacy filmmaking, and rushed to completion (though never looking it) in time for its world premiere last night at the 52nd New York Film Festival, Citizenfour is likely to open the eyes — not to say change the minds — of doubters who would like to see Snowden tried for treason.

It’s a devastating account of how 9/11 was used to justify the abrogation of civil liberties on an unimaginable, even global scale as the National Security Agency spread a metastasizing net to intercept and track the telephone calls and Internet activities of millions. Equally significant, it’s the compelling story of a quiet American moved to action by nothing more complicated than a determination to expose what he considered to be a lawless, immoral operation.

Poitras identifies Citizenfour as the final chapter in a trilogy that follows her previous My Country, My Country, about the Iraq war,  and The Oath, about Guantánamo — celebrated investigations of wayward American policy in the wake of the 9/11 attacks. The new film — from RADiUS, in association with Participant Media and HBO Documentary Films — will be released on October 24. It begins in January 2013 with a voiceover, presumably Poitras herself, reading an encrypted email from “citizenfour” outlining some of the basics of the surveillance machinery and information gathering already in place.

Glenn Greenwald Presents His Book 'No Place to Hide: Edward Snowden, The NSA, And The U.S. Surveillance State'Over the next several months, Poitras and reporter Glenn Greenwald get a more nuanced understanding of the astonishing parameters of Snowden’s documentation and arrange to meet him at a Hong Kong hotel. Over the course of several days in June they interview the on-the-lam analyst and begin releasing stories in The Guardian.

The news is, of course, explosive, and one of the film’s more intriguing points is that Snowden — slight, usually bespectacled and without any guile — makes it clear that he plans to be exposed and doesn’t want anyone else being blamed for his choice to come forward. And yet when the media frenzy begins (along with the inevitable Administration lies and denials and the calls for his head on a block) Snowden’s fear becomes palpable even as his determination remains unwavering — especially his determination that he himself not become the story. He isn’t angling for the cover of People.

Through it all, Poitras and her camera refuse to sensationalize (despite some forbidding background music by Nine Inch Nails’ Trent Reznor and Atticus Ross), as the interviews unfold in seeming real-time. She introduces other key players in the story as well, notably William Binney, a crypto-mathmetician and former NSA director responsible until his own disillusionment for much of the technology used in wide surveillance. If there is a top villain, it is the President himself, signing off on secret orders to expand the surveillance while pretending in public to champion the sanctity of privacy. Tell it to Angela Merkel.

The final scenes record Snowden and his partner, Lindsay Mills, cooking a meal in their secluded Russian home, where they are living on a longterm visa. And in a stunning reveal, Snowden learns that Greenwald, Poitras and Jeremy Scahill, another journalist they’re working with, have begun talking to a whistleblower with an even higher level of access than Snowden’s. You can’t tell whether “citizenfour” is more shocked, relieved or devastated by his vindication. Doubtless all three in equal measure.