'The Unknown Known' (PG-13)

The Unknown Known is history and philosophy — colored, compelling and sometimes convoluted — told through some of the possibly millions of memos Donald Rumsfeld dictated during his career. An estimated 20,000 alone were crafted during the George W. Bush administration.

The two-time secretary of defense composed so many, issued on white paper, that they were dubbed “snowflakes” and they kept fluttering and flying through his service in Congress, the White House and the Pentagon.

It was after being elected to the House of Representatives in 1962 that Rumsfeld started dictating notes about how he voted and why, along with details about the legislation and amendments.

Documentary filmmaker Errol Morris (The Fog of War, The Thin Blue Line) sits down with Rumsfeld and asks him to elaborate on some of the memos he wrote, along with the events he witnessed and helped to shape, including the Iraq War.

Memos and talking heads make this sound like a snooze-fest, but it’s not, thanks to archival footage and photos, Danny Elfman music and the 33 hours Morris spent with his subject, who had a front-row seat to history for a half-century.

He draws Rumsfeld out, using his own words — including the puzzlers which, now and again, befuddle even the author.

Rumsfeld had explained what he calls “known knowns, known unknowns, unknown unknowns and unknown knowns.” (This wordplay, part of a response to a reporter’s question about Saddam Hussein and terrorists seeking weapons of mass destruction, also would inspire the title of Rumsfeld’s 2011 memoir.)

That last category of “unknown knowns” refers to “things that you think you know that, it turns out, you did not.” At least that’s what the memo stated, although, later in the documentary, Rumsfeld realizes that’s not what he meant.

“I think that memo is backward. I think that it’s closer to what I said here,” he amends, referring instead to “things that you possibly may know that you don’t know you know.”

Got that? Head spinning and reliance on dictionary definitions aside, The Unknown Known shares Rumsfeld’s insights on a range of subjects:

On Dec. 7, 1941: “Pearl Harbor was a failure of imagination. We didn’t know that they could do what they did, the way they did it.”

On what President Gerald R. Ford said when Rumsfeld and a Secret Service agent covered his body after an assassination attempt by Sara Jane Moore: “Come on, you guys, get off. You’re heavy.”

On unfounded rumors that Ronald Reagan would pick former President Ford as his 1980 running mate: “It’s like sticking four hands on the steering wheel. You’re gonna end up putting the truck in the ditch.”

On many Americans’ belief that Saddam Hussein was connected to the 9/11 attacks rather than Osama bin Laden and al-Qaida in Afghanistan: “I don’t think the American people were confused about that.”

On Guantánamo Bay: “I’ve never seen so much misinformation communicated about a place as Guantánamo. The prison was exceedingly well run.”

Morris acknowledges, in production notes for the film and elsewhere, that he went into the movie with strong opinions about this subject. Every now and then, a tone of incredulity creeps into his voice.

“I was very much against the Iraq war, and I still am — I think it was a terrible mistake,” Morris says. “But I believe I made this film in the spirit of inquiry with a genuine desire to investigate, a desire to find out something that I might not have known before.”

He could have created “the frisson of a clash where the interview subject gets up and walks out of the room in a huff” but that wasn’t his intent, says the filmmaker, who took a different tack in Standard Operating Procedure about the abuses at the Abu Ghraib prison.

Outsiders such as Condoleezza Rice, who once was the subject of a pointed 2002 memo about the “chain of command,” are not asked to weigh in. Neither are historians, recipients of the memos or even the underlings who transcribed the Dictaphone messages.

This is about the man and his memos, and Rumsfeld comes across as unapologetic or perhaps secure in his choices, shrewd or wily depending on your perspective and a vigorous 81-year-old who enjoys the muted thrust and parry of the interviews.

He’s still full of contradictions, “Rumsfeld rules” and ripostes such as, “The absence of evidence is not evidence of absence.” The blizzard of snowflakes is over but the battle for a vaunted place in history remains.

With: Donald Rumsfeld.

Director: Errol Morris.

A Radius-TWC release. Running time: 103 minutes. Vulgar language, brief nudity. Opens Friday April 25 in Miami-Dade only: O Cinema Wynwood.