A STARTLING and unprecedented documentary, The Gatekeepers is about two things: the nature of national security and the costs of keeping it. Focusing on the state of modern Israel—a place, in some regards, that our own country is starting to resemble—the film consists mostly of interviews with the last six heads of the Shin Bet, Israel's equivalent of the FBI and Homeland Security. These are men who made some of the toughest calls in their country's "War on Terror," and their perspectives are unique and harrowing.

Candidness is a strange thing when it comes to national security: All of us resent platitudes and double talk when it comes to the application of deadly force, but the alternatives can be just as unsettling. That realization comes fairly early in The Gatekeepers. Here are six men whose day jobs involved regularly ordering the deaths of other human beings. There's a scene in which one man—a man who could be my uncle—talks about ordering the murder of two men in custody. Even this far removed, it's a deeply uncomfortable thing to witness.

At the same time, they also discuss the costs of their actions. They had to become weapons in the service of the state—ethics and morality aren't useful concepts in their line of work. Still, hearing them discuss the moral hazards of ordering even a "clean" kill is heartbreaking—or, at least, it is from the perspective of someone who's never had to order the death of anything more sentient than a chicken sandwich.

The Gatekeepers is an essential film. These are the kind of men who execute national policy, and there is no better way of explaining how they do so than in their own words.