THE PENTAGON tries so, so very hard to come off like a war reporter's best friend.

In Afghanistan, now in its 12th year of combat, military brass kindly warn truth-seekers not to venture too far from the safe zones our soldiers have carved out—dispensing, instead, photo ops and press releases meant to keep reporters healthy and alive and their overseas editors somewhat happy.

But scaring the shit out of lazy journalists is hardly an act of decency. It also lets the Pentagon keep the brutal truth of occupation—relentless drone strikes, dead women and children, mistakes, cover-ups—conveniently hidden from an increasingly complacent American public.

That is, until one reporter or another decides it really is worth risking her ass to peel back the propaganda curtain. And someone always does. This time it was Jeremy Scahill—the muckraker extraordinaire for the Nation who first revealed Blackwater's deep, unaccountable involvement in Iraq.

Scahill's new documentary, Dirty Wars, charts how a single renegade trip to the Afghan town of Gardez—where a wedding party had been shot up by "bearded Americans" in the dead of night—unearthed evidence of the military's most sensitive secrets, like Barack Obama's "kill list" (that includes Americans) and the shadowy spook-commandos the White House sends out to enforce it, anywhere in the world it wants. (Scahill, it turned out, was outing the same Joint Special Operations Command later responsible for killing Osama bin Laden.)

Dirty Wars unfolds slowly. But it minds its unfolding mysteries and builds in urgency like any capable thriller should. The telegenic Scahill jumps from Afghanistan to Yemen to America, meeting like-minded moles in the military and figuring out the government is watching him right back.

He also turns casualties and collateral damage back into human beings. Scahill obtains heartbreaking footage of the Afghan wedding party—happy, joyous—moments before the doors are blown open in a mistaken raid and bullets fly. (Soldiers later carved bullets out of the bodies in a failed bid to avoid discovery.)

Most importantly, Scahill reminds us that the most potent seeds for the radicalization we're struggling to stamp out are the corpses we're leaving behind.

Headlines in recent days, about intrusive government data mining and surveillance, tell us that leaks have become the most dramatic weapon in the fight against a national security apparatus clearly willing to justify any means to what's become an ill-defined end: "security."

But Scahill's journalism—built on courage, relentlessness, and shoe leather—should stand as an important reminder that leaks are not the only way to poke Big Brother in the eye.