If any film other than Laura Poitras’s “Citizenfour,” an unsettling look at pervasive electronic snooping by the United States government, wins the Oscar for best feature documentary, it will constitute a huge upset. With the whistleblower Edward Snowden as its main subject, “Citizenfour” doesn’t just recount recent history, it actually puts a camera in the room as Mr. Snowden makes one explosive revelation after another to Ms. Poitras and other journalists.
That’s not to say the remaining nominees don’t have their merits. A pair were directed by two-man teams and are about photographers: “The Salt of the Earth,” by Wim Wenders and Juliano Ribeiro Salgado, is a look at the career of Sebastião Salgado, one of the most celebrated photographers of our time, while “Finding Vivian Maier,” directed by John Maloof and Charlie Siskel, examines the life of a Chicago-based nanny whose work became known only after her death in 2009.
Rounding out the field are two films set in conflict zones. Orlando von Einsiedel’s “Virunga” is, at least on its surface, about efforts to save endangered mountain gorillas in Virunga National Park in the Democratic Republic of Congo. But poachers may be the least of the animals’ problems, as a civil war rages around them and a British oil company with ties to corrupt officials also shows up. And in “Last Days in Vietnam,” Rory Kennedy tells the story of the American withdrawal from Saigon in April 1975, focusing on embassy officials who tried to evacuate as many of their South Vietnamese colleagues as possible.
But “Citizenfour” has various advantages over its competitors. Some are purely cinematic: Ms. Poitras has found an interestingly dramatic way to show email correspondence, and is telling a real-life story that has all the elements of a thriller, elements that she emphasizes in a way that makes Mr. Snowden, a former National Security Agency contractor, seem almost like a Jason Bourne.
Beyond that, however, Ms. Poitras benefits from her choice of subject and the tribulations she faced in making “Citizenfour,” whose title comes from the screen name Mr. Snowden used when he first contacted her. Mr. Snowden’s revelations, which made him a hero to some and a traitor to others, affect every American citizen and millions more abroad, so audiences — and Academy voters — come to the film with some…