Alex Gibney’s The Armstrong Lie certainly can’t be faulted for how little distance exists between its subject matter and the circumstances of its production. That fault lands squarely in the harried, disgraced lap of Gibney’s subject, Lance Armstrong. In 2009, the Oscar winner set out to make what he thought was going to be a comeback piece on the controversial Tour De France legend Armstrong, a film that would highlight the cyclist’s return to competition as he attempted to dispel rumors that he would no longer be able to race at his peak when faced with an intensive, often invasive battery of anti-doping tests throughout the Tour.

And then, as we now know, Armstrong got caught.

At a glance, Gibney seems like an odd choice for the film within the film, the inspirational character study of a man reviled by so many of his former friends and teammates. Even within The Armstrong Lie, during the filming of the 2009 Tour, Gibney acknowledges that many of his peers called into question why a director of such reputation would lend his skills to what most considered a puff piece. It’s a question that The Armstrong Lie never really answers (though even some of the pre-collapse interviews suggest an investigation into the suspect culture of star athletes in America), but it doesn’t have to. The minute Armstrong sat down with Oprah Winfrey and said “yes” to a series of indiscretions he’d spent his life denying, The Armstrong Lie became a very different documentary.

And for the most part it’s a good one, and at the very least it’s one to which Gibney is perfectly suited. Most of his work surrounds, in one way or another, the self-generated mythologies of supposedly infallible institutions. Whether it’s a career politician (Client 9), a board of directors (Enron: The Smartest Guys in the Room), a folk hero/rogue journalist (Gonzo: The Life and Work of Hunter S. Thompson) or the U.S. military (Taxi to the Dark Side), Gibney has made a career out of examining men who considered themselves (or were considered) too big to fall. The commonality: in one fashion or another, they all did. Few figures in American popular culture are more beloved than the star athlete, and Armstrong transcended that. He became the defining face of a sport notorious for its under-the-table dealings, and somehow convinced the skeptical public that he was different, right up until the moment he couldn’t keep the lie alive any longer.

The film, for its part, paints a convincing picture of how much hustling was involved in Armstrong’s ever-growing con. Friends were tossed aside, showed his true face (variations on “He’s an immensely intimidating person” pop up regularly throughout the film), invalidated before the entire world so that Armstrong could keep going. Gibney’s film does beat this point into the ground at times, particularly in the early going; there’s a prevailing feeling during these stretches that Gibney’s indignation at being turned into yet another patsy dictated the film’s cadence too often. (Much of the later, post-confessional interview between Gibney and Armstrong involves Armstrong seemingly being wrung for contrition, which he hardly seems willing to offer.)

Once the film stops recapping the Oprah interview and thumbing its nose at Armstrong, however, The Armstrong Lie evolves into an intriguing breakdown of a sport corrupt to its core, and of the pressures on star athletes to keep topping their own legends before a public hungry for new reveries, no matter the consequences. And, most importantly, Gibney’s film captures a man who’s still fighting the good fight, defiantly showing off his Tour jerseys on Twitter for an increasingly unsympathetic public. When The Armstrong Lie is able to set aside its own vendettas and simply observe, it offers a sad and mildly chilling central thesis: What good does vindication do the public, if the man on the receiving end still doesn’t think he did anything wrong? For Gibney, the answer is rather simple. The rest of the world will move on, and soon he’ll be arguing with nobody at all, another star athlete who let the people down.