As we learn in the final installment of the post-9/11 trilogy from documentary filmmaker Laura Poitras (The Oath), Big Brother is no longer content with watching. He now listens in on our phone calls, reads our email, looks over our shoulder as we surf the web and tracks our movements as we go about our business. Even when our business has nothing to do with terrorism.

We learn the degree to which privacy has been outlawed just as the film shows Poitras and fellow journalist Glenn Greenwald (who recently earned a Pulitzer for his reporting on the subject) learning it for themselves. Citizenfour is the code name that NSA whistleblower Edward Snowden used when initially contacting the pair, whom he'd selected as conduits for getting his revelations to the public. Poitras' mindblowing film chronicles several days during the summer of 2013. The three spent that interval in a Hong Kong hotel discussing the classified information before they dropped one of history's biggest bombshells.

When I say privacy has been "outlawed," I'm not kidding. In October 2012, we now know, President Obama secretly signed a little something called Presidential Policy Directive 20. Sounds innocuous, right? It's only the legal basis for the power the NSA and FBI now have to access our phone records from the telecoms while tapping into our personal data from internet behemoths like Yahoo and Google.

We've seen Snowden's face countless times, but the film offers viewers their first opportunity to get a sense of who he is. In all probability, you'll be surprised by the 31-year-old you meet. He comes off as highly intelligent, slightly shy and, yes, patriotic. It's clear Snowden realized the danger he was placing himself in, and equally clear that his sole motivation was warning the American people that, without their knowledge or consent, their government is using taxpayer funds to build "the biggest weapon for oppression in the history of mankind."

"A week after 9/11, they began actively spying on everyone in this country," confirms former NSA technical director William Binney. The chilling takeaway: Nobody involved even bothers to pretend this is about terrorism anymore. In some cases, information about foreign corporations winds up in the hands of American corporations. In others, information about American citizens is simply "absorbed" and stored. Today everyone has an FBI file. You no longer need to be under suspicion to be under surveillance.

What an astonishing, immeasurably important historical document this is (on top of being a lock for the Best Documentary Oscar). As a work of cinema, Citizenfour has as much in common with a Bourne-style tale of international intrigue or a Hitchcockian suspense-fest as it does with a traditional political documentary. The more Snowden reveals about the capabilities of today's cyberspooks, the more the movie's sense of dread mounts.

We watch Poitras beating it to Berlin when the files start being released and she realizes she's being followed. Snowden and his partners cut off their email communications when they become aware that even they can't encrypt messages to the point where they're impregnable by the forces trailing them.

Which, come to think of it, means any sympathetic journalist — or reviewer — typing on a computer keyboard about this unparalleled violation of rights is likely to be added to some shadowy master watch list. And our government will deny the existence of that list until someone as courageous and principled as Snowden makes it public.

Yikes. I've got a wife and kids. Plus zero interest in moving to Berlin. Forget everything you just read. What I meant to say is, "Penguins of Madagascar is frosty fun for the whole family!"