Oscar voting is ongoing through Feb. 25, and a rule change could affect the outcome of one of the year’s most interesting categories: documentary feature.

The five excellent contenders fall into roughly three categories: feel-good movies (“20 Feet From Stardom” and “Cutie and the Boxer”), world politics (“Dirty Wars” and “The Square”) …. and “other.” The fifth contender, “The Act of Killing” (in photo above), is hard to classify, which is its greatest strength and its area of vulnerability.

This is the first year that all Academy members can vote on the honor system for docu, as opposed to showing proof that they’ve seen all five. The Academy of Motion Picture Arts & Sciences sent out screeners of the quintet (as well as nominees in some other categories), so voters should watch all of them before voting.

As for the two that are feel-good (but with substance), “20 Feet From Stardom” (the highest grossing of the five, with $4.8 million domestically) and “Cutie” both deal with the highs and lows of being a creative artist, which will obviously appeal to Acad members. They follow such recent docu winners as “Man on Wire” and “Searching for Sugar Man.”

“Dirty Wars” and “The Square” are, respectively, uncompromising looks at America’s covert operations overseas, and Egypt’s ongoing revolution. In the recent past, Oscar voters have rewarded such fare, including “Taxi to the Dark Side” and  “The Fog of War.”

Errol Morris, who won an Oscar as director of the 2003 “Fog,” introduced some filmmaking innovations in documentaries, such as re-enactments and dramatic music scores (e.g., Philip Glass). Morris has high praise for “Killing,” saying, “One of the things that’s extraordinary about documentary film: You get to reinvent what it means to make a documentary every time you make one.  Josh (Joshua Oppenheimer, director of “Killing”) has certainly done that, taken the form and created something unique and different.”

Morris says his admiration of the film may not be objective. “It’s an odd position because I’m executive producer of film and have known Josh for years. But my feelings about the movie go beyond that. I’m very proud to be connected with this movie.”

Oppenheimer spent a long time in Indonesia trying to make a film about survivors of a 1965-66 genocide (estimates vary, but a frequently cited figure is 500,000 deaths). But the survivors were afraid to talk because the killers were still in power. So Oppenheimer and his team shifted focus to these men, who bragged about their murders and offered to re-enact some of them, eventually performing the re-enactments in the style of Hollywood film genres, such as Westerns and musicals.

“The film tries to capture a mystery, without answering questions,” says Morris. “These are people who committed terrible crimes and were never punished — and it’s about how they see themselves and what they have done.”

It’s fascinating viewing for Westerners, but may make them uncomfortable, partly because it’s so surreal. But also because there have been claims that America was involved. But the issue of U.S. awareness were rarely raised because the country was simultaneously involved in Vietnam, which got all the attention. As a result, many Americans today are unaware of the Indonesian events.

Describing Oppenheimer as “a kindred spirit,” Morris said, “The film represents essential activism, Josh’s commitment to revealing Indonesia’s hidden past.” But it also asks Westerners to examine their relationship to the past. So are awards voters in the mood for tough truths or creative crises?

Either way, Morris is fine with the Academy’s rules. The danger is that members will vote based on having seen only three or four documentaries. The good news is that it opens up docu voting to thousands of people as opposed to a much smaller number.

Morris concludes, “Documentaries should not be treated differently from other kinds of filmmaking. With nominations for best film, best director, best actor, anyone can vote. It should be the same for documentary.”

So that’s the bottom line: See all five, and then vote.