Donald Rumsfeld smiles, spins and passes the buck as he spars with Oscar-winning documentary filmmaker Errol Morris in "The Unknown Known." Rumsfeld — so dismissive of any questioning of his thinking and decision-making in scores of news conferences over the decades — has the certitude of a man who figures this film guy won’t lay a glove on him. Rumsfeld will make his arguments about the hindsight of history, suggest that "mistakes were made," admit to none of his own, and that will be that.

But Morris, who memorably dissected an earlier defense secretary (Robert McNamara) in "The Fog of War," is a persistent interviewer and smart in his own right. He may not score a knockout "gotcha" here, as he engages in a battle of wits, wills and semantics with "Rummy." His film still exposes the omnipotent architect of the Iraq War, the War on Terror and its subsequent fallout as, if not chastened, at least needy: He needs this chance to salvage his rep more than Morris needs yet another history lesson of a campaign that failed.

In the Morris style, the movie is in Rumsfeld’s own words, spoken straight at the camera. Occasionally, Morris, off-camera, persists in a line of questioning the way no TV anchorman ever would.

"Why the obsession with Iraq and Saddam?"

‘THE UNKNOWN KNOWN’ Rated: PG-13 Opens Friday at Kahala 8

Mostly, though, this is Rumsfeld, answering or evading questions and reading from his "blizzard" of memos from his years of public service.

As with McNamara, Morris expounds on Rumsfeld’s entire life, picking up the ambitious congressman who played all the angles in the short-lived Gerald Ford administration, shafted George Herbert Walker Bush in ways the elder Bush never forgot (Rumsfeld chuckles over this) and, with his former subordinate and lifelong pal Dick Cheney, ran U.S. foreign policy for the better part of a decade.

"I’m cool and measured," Rumsfeld says, brushing off the Morris suggestion that Iraq was a George W. Bush administration "obsession." He articulates the Rumsfeld Doctrine, installing "new regimes in states that sponsor terrorism."

He denies that he and his Bush II colleagues set out to "confuse" the American people, post-9/11, into thinking Saddam Hussein had a hand in the attacks of Sept. 11, 2001. Then Morris shows a news conference where Rumsfeld does his best to perpetuate that confusion.

His famous bluntness and glib sarcasm are softened, his memories of the Ford-era abandonment of Vietnam fuzzy. The accusations of his "Machiavellian" White House back-stabbing roll off his back. He sleeps at night.

It’s the memos, revealing both his style of management (bullying) and his way of thinking that are most revealing, which is why Morris gets him to read them, most famously the "unknown knowns" one. Rumsfeld aptly compares 9/11 to Pearl Harbor as similar "failures of imagination." It’s not just the intelligence you have in hand, it’s the intelligence that you don’t that creates such fiascoes.

And there are "things you think you know that it turns out you did not." Thus, Bush II’s "obsession" with Saddam when al-Qaida was the real threat. Thus, Rumsfeld’s finger-pointing at George Tenet of the CIA, his arrogant power grab from Secretary of State Condoleeza Rice (in memo form), his wordplay to justify blunders. ("The absence of evidence is not the evidence of absence.")

Morris, politely confrontational when his voice crops up, undercuts the tension of the interviews by jump-cutting Rumsfeld’s answers, not waiting, hoping he’ll hang himself. He uses the advantages of a film editor to insert TV news footage to make counterarguments to Rumsfeld’s version of himself and the events he took part in rather than throwing those in Rumsfeld’s face.

So while it’s a valuable document, a long-form interview with an important figure of ’70s, ’80s and 21st-century American foreign and defense policy, "The Unknown Known" never rises to "Frost/Nixon" or even "The Fog of War." We get a taste of the man behind the bluff and bluster and remember to be wary of those so sure of themselves that they refuse to brook any hint of second-guessing. And we realize that the cryptic, calculating Donald Rumsfeld himself may be the ultimate "unknown known."

Review by Roger Moore, McClatchy Newspapers