Alex Gibney’s new documentary charges keenly into the dense meta-fog of an information-age war between transparency and opacity. There’s never a dull moment on these front lines, even when it seems like all Gibney has to cut to is one more secondhand shot of Julian Assange gazing wordlessly into a laptop. Which is to say the secret-sharing crusader remains as mercurial as ever, leaving us to piece together his journey from scrawny teen hacker to rumpled political rock star to cause-martyr and scandal-plagued, vaguely Hughes-ian recluse. Also hovering around these proceedings is Assange’s most important source, U.S. Army private Bradley Manning, whose tortured-soul testimony piles up in heaps of confessional e-mail. With other articulate talking heads including journalists, former insiders, and government muckety-mucks, Gibney gives a fine backgrounder on how WikiLeaks’ business of big reveals traded up from the Icelandic financial system to the American wars in Afghanistan and Iraq. He also bears in mind the serious ethical question of what happens when blowing a whistle might put lives at risk. (Some of what happens, inevitably, is a media circus.) We Steal Secrets gathers power from circling back to a WikiLeaks coup, the harrowing 2007 footage of a wanton American helicopter assault on a group of noncombatant Iraqis, including two journalists. It seems grimly telling that this story’s most crucial moment may have occurred when someone mistook a camera for a weapon of war.