VENICE - Venice festival scheduling is a business that can seem haphazard at best, and perverse at worst. Kim Ki-duk's castration-and-incest bonanza "Moebius" straight after breakfast? Sure. Philip Groning's three-hour, 59-chapter dissection of domestic abuse to finish the day? Hey, why not? Sometimes, however, they let on that they really know what they're doing with a juxtaposition that seems too perfect to be accidental -- and they don't come much more effectively on-the-nose than last night's back-to-back double bill of Alex Gibney's "The Armstrong Lie" (B-) and Errol Morris' "The Unknown Known" (C+). (Even the titles have a pleasingly similar cadence.) It wasn't labelled in the programme as The Great American Douchebags Special, but we got the idea.

Perhaps it's a side effect of viewing them with only a 20-minute, theater-traversing in between, but the films seemed too well-matched -- not just in content, but in a number of their strongest and weakest points -- to review separately, even if they'll rarely be re-partnered outside the festival environment.

Of course, it'd be a pretty vapid line of criticism to directly equate the docs' subjects. Having finally admitted guilt after years of strenuously denied doping allegations -- and having been unceremoniously stripped of his record seven Tour de France titles -- cyclist Lance Armstrong may be the biggest fraud in the history of recorded sport, but his sins have largely come at his own expense. That's something that can't be said for former US Secretary of Defense Donald Rumsfeld, whose strenuously denied errors of judgement in the Iraq War came not only at significant human cost, but at the already frail international political credibility of his country. Degrees of media fascination may suggest otherwise, but one is plainly a drop in the ocean of another.

What they have in common -- and what seems principally to aggravate Gibney and Morris, both occasionally audible in their films as rather animated interviewers -- is a certain faith-breaking status in contemporary American culture, a legacy of public distrust that, particularly in the case of a more romantic figure like Armstrong, has been symbolically extrapolated to realms beyond their personal reach. Rumsfeld certainly wasn't the only one making terrible, uninformed decisions in that fraught period of US political history, but for a few years, it seemed his thin smile and rimless spectacles were the all-purpose face of American institutional corruption -- arguably even more so than his equally widely loathed Commander-in-Chief George W. Bush, if only because Rumsfeld was so much more articulate, and therefore more insidious to his detractors.

Armstrong, by contrast, has no political agency, but his long-term feat of self-elevating deception -- perhaps more immediately comprehensible to the general public in terms of its moral transgressions than Rumsfeld's political acts, and more prone to salacious media interpretations -- betrayed an ideal of American heroism that the global public had invested in to a considerable degree. Nobody expects politicians, even the ones on the side of right, to be all that honorable. (We do, however, want them to be competent.) But the good-looking cancer survivor who battles the odds to become a world-beating athlete and lead-by-example philanthropist? When he turns out to be an illusion, nobody dies -- but people are hurt anyway.

Gibney is one of those people. Normally the coolest of customers, the prolific documentarian here lets a passive-aggressive tone of disenchantment, even anger, seep into his filmmaking that speaks less of a admirer's aggrievement than of a professional's annoyance at having had the wool pulled over his eyes. Gibney started this documentary with a very different motivation in 2009, chronicling Armstrong's attempted Tour de France comeback -- regardless of the outcome, his last professional hurrah before he was conclusively rumbled as a doper -- with the intention of discovering just what made this supposed human superman tick.

Guy Lodge is a South African-born critic and sometime screenwriter. In addition to his work at In Contention, he is a freelance contributor to Variety, Time Out, Empire and The Guardian. He lives well beyond his means in London.