There are two ways to look at “Citizenfour,” Laura Poitras’s documentary about Edward J. Snowden, the former National Security Agency contractor whose revelations of widespread surveillance launched a hundred Op-Ed columns a year ago. The first and most obvious is as a piece of advocacy journalism, a goad to further argument about how security and transparency should be balanced in a democracy, about how governments abuse technology, about how official secrets are kept and exposed. The second is as a movie, an elegant and intelligent contribution to the flourishing genre of dystopian allegory.

Those who regard Mr. Snowden as an unambiguous hero, risking his freedom and comfort to expose abuses of power, will find much to agree with in Ms. Poitras’s presentation of his actions. This film is an authorized portrait, made at its subject’s invitation. In 2013, Mr. Snowden, using encrypted email under the alias “citizen four,” contacted Ms. Poitras and the journalist Glenn Greenwald, inviting them to meet him in Hong Kong, where he would share what he had learned about the N.S.A.’s capacity to intercept data from the phone calls, emails and web wanderings of American citizens. When asked why he had chosen her, Mr. Snowden, his identity still electronically shrouded, replied that she had selected herself, based on her previous work as a journalist and filmmaker, including a short documentary about William Binney, an N.S.A. whistle-blower who also appears in “Citizenfour.”

And “Citizenfour,” much of which consists of conversations between Mr. Snowden and Mr. Greenwald, emphasizes his bravery and his idealism, and the malignancy of the forces ranged against him. This is obviously a partial, partisan view, and several journalists on the national security and technology beats — among them Fred Kaplan at Slate and Michael Cohen (formerly of The Guardian) at The Daily Beast — have pointed out omissions and simplifications. Those criticisms, and George Packer’s long, respectful and skeptical profile of Ms. Poitras in a recent issue of The New Yorker, express the desire for a middle ground, a balance between the public right to know and the government’s need to collect intelligence in the fight against global terrorism.