‘Risk’ Is a Perceptive, Subtle Portrait of Power and Posture

Billed by some as a prequel to ‘Citizenfour,’ Laura Poitras’s new film has a much more complex relationship to her previous work.

In October 2012, Lady Gaga paid a visit to Julian Assange at the Ecuadorian Embassy in London. At the time, no one was entirely sure what to make of it, a publicity stunt of the strangest order. The most memorable image was a …