How much do you actually know about Edward Snowden? What about the National Security Agency (NSA) and its domestic surveillance program? I suspect most Americans would know that the two are forever intertwined as a result of the revelatory information Snowden, an NSA contractor, leaked to journalists in 2013. And I suspect most also feel strongly about Snowden, one way or another.

But I think the answers to those two questions are, in order, virtually nothing at all and just a little bit.

Laura Poitras' documentary, Citizenfour, filmed almost exclusively in the Hong Kong hotel room where Snowden holed up as he divulged thousands upon thousands of classified documents to Poitras and journalist Glenn Greenwald begins to fill in the blanks. That job may never be completed, and if it ever is, we'll need the benefit of decades of hindsight to know it is finished. But this is a much-needed start.

It should come as no surprise that Poitras' portrait of Snowden is a sympathetic one, considering his relationship with her and Greenwald. These are the people he has handpicked to share state secrets with, and the admiration runs both ways as a result. "Ed" as he likes to be called is nervy and paranoid, hints of panic just beneath the surface of a composed facade. His intimate knowledge of the U.S. surveillance state makes a Hong Kong hotel room seem well within its grasp, and everything from a phone receiver to the fire alarm testing seem suspicious.

He is also just a kid, pale, baby-faced and perpetually sporting a five-o-clock shadow, perhaps because he can’t grow facial hair beyond that. He has a girlfriend he left behind in Hawaii. He has family and friends and now former colleagues. Astonishingly, their well-being seems to be his biggest worry even as he throws his life away.

Finally, as the story unfolds, it becomes harder and harder to argue that Snowden, even if you think he is a criminal, is not at the very least a man of conviction. He is uncomfortable with being filmed at all at first. Much of the film’s tension comes from his eventual decision to reveal his identity, a decision he makes grudgingly. He does not want the story to be about him, and yet he concludes that coming forward will shield the loved ones he is most worried about from harm. Snowden leaked documents that exposed a massive government spying program out of a genuine belief that he was doing the right thing. You might disagree with him, but, after watching Citizenfour, I think you will be hard-pressed to contend that he was motivated by a bizarre and narcissistic quest for fame.

Snowden’s reluctance to enter the spotlight is a cruel twist of fate. He wants the focus to be on the NSA, and if you take his word over the people who have tried to discredit him, it unquestionably should be. But the measure of the man matters in this case. Snowden might not wish to be measured at all, but his actions make it a virtual necessity.

Sizing him up after seeing this documentary, I am more inclined than ever to see him as an American hero. The breadth of the NSA’s spying program — the volume of information it is collecting on American citizens (to say nothing of the people Americans share this world with) — is disturbing and very probably illegal, no matter how their actions are being passed off right now. Snowden himself gave up just about everything to bring all of that to light — to at least give it a chance to enter the public discourse.

That it might be drowned out by a government that is, at best, entirely complicit in the surveillance state or ignored by a jittery, frightened, disengaged populace still reeling after 9/11 is a shame. But it doesn’t have much to do with Snowden himself, a man who, thanks to Poitras’ claustrophobic, pulsing footage of the moment he became a household name, looks more than ever like a selfless patriot.