From Errol Morris’ hypnotic "The Unknown Known," it is impossible to tell if former Defense Secretary Donald Rumsfeld has ever felt badly about any decision he has ever made. Regrets, had he a few?

Nope, not that he lets Morris know about, the latter of whom knows a thing or two about long interviews with hideo— um ,complicated men. (See also "The Fog of War," his movie on Robert McNamara and "Mr. Death," his portrait of intensely weird electric-chair-modifier-turned- Holocaust denier Fred A. Leuchter.)

The title refers to Rumsfeld’s idea that there are known knowns (stuff you know to be correct), known unknowns (stuff you don’t have nailed down), unknown unknowns (stuff you don’t know you don’t know) and unknown knowns (stuff you think you know but do not). Got that?

There are no moral quandaries, no complex moments that Rumsfeld can’t smile about at the end of an explanation. It must be reflexive, that smile. Nobody could be that crass about the lack of weapons of mass destruction in Iraq, could they?

A devout memo-writer, Rumsfeld reads many aloud. He calls these endless missives — comments that changed the course of countless lives — "snowflakes" because they are on white paper. Isn’t that adorable? Fond of citing the dictionary at press conferences (and focusing on how the other side, whatever it is, isn’t quite using a word correctly), Morris has definitions of various words pop on the screen.

We learn a bit about the young Rummy, his life-long marriage ("I didn’t want to get married but I sure as heck didn’t want her marrying anyone else"), his time in Congress and various pre-W. jobs in the Nixon and Ford administrations (and you better believe Rumsfeld looks like he enjoys reminding us that Dick Cheney used to be "my deputy.")

Sure, he thinks it would have been better for the country if President Bush had accepted his resignation after the abuses at Abu Ghraib were revealed, but that’s not quite the same thing as saying, "Yup, my bad."

One wonders if President Bush declined his resignation out of knowledge of Rumsfeld’s past ability to exit administrations with his skin intact. Rumsfeld escaped the Nixon White House unscathed by Watergate and moved from Chief of Staff to Secretary of Defense under Ford.

At no moment does Rumsfeld ever quite cop to anything, does anything ever stick. On WMDs: "The absence of evidence is not the evidence of absence." He even denies reading the Justice Department memos on the legality of torture, which is a astonishing to contemplate. ("Everything is astonishing in hindsight," Rumsfeld says of Pearl Harbor and 9/11. Aren’t things supposed to become clearer in hindsight? Can we look up that word, please?)

As for the unknown known itself, well, Mr. Secretary, we mere mortals call those mistakes.