Incendiary: The Willingham Case” may be the “Moneyball” of political documentaries.

Granted, this movie doesn’t star Brad Pitt as a scrappy baseball manager who leads a ragtag team of players to a historic winning streak. But “Incendiary” — a riveting true-crime documentary from the Austin-based filmmaking team of Steve Mims and Joe Bailey, Jr. — delivers just as timely and meaningful a message about the importance of honoring empirical facts over gut feelings and irrational biases.

Nominally about a death row case that became a flagship for anti-capital punishment activists in Texas, “Incendiary” also offers a rare glimpse of three-time governor and Republican presidential candidate Rick Perry in action. Among other things, “Incendiary” provides the most unsettling example yet of Perry’s now-famous disregard for science — in this case the arcane forensics of arson investigation.

What’s more, the documentary stands as a methodical, dispassionate corrective to film portraits of political figures that too often rely on passion and partisan fervor to make their points, rather than provide a fact-based illumination of their subjects’ records or character (Sarah Palin being the most recent subject of both hagiography and ad feminam tear-down).

The Willingham case of “Incendiary’s” subtitle began in 1991, when Cameron Todd Willingham escaped his burning house in Corsicana, Tex., leaving his three young daughters behind to perish in the blaze. Willingham was accused of arson murder and, refusing to plead guilty and receive a life sentence, was executed in 2004. “Incendiary” makes a persuasive case that the arson investigation leading to the charges against Willingham was dramatically flawed, based on outdated, unscientific methods that, around the time Willingham was arrested, were in the process of being overhauled.

Had those methods been acknowledged by the authorities — from Willingham’s lawyer, who believed his client was guilty, to Perry, who refused to sign even a 30-day reprieve so that new facts could be brought to bear in the case — Willingham would not have been put to death and, in time, he may have been exonerated.

“Incendiary’s” most convincing witnesses to the grievous miscarriage of justice in the Willingham case are Gerald Hurst and John Lentini, an accomplished chemist and a veteran fire investigator, respectively, who lead viewers on a fascinating tutorial on the history of arson investigation — the traditional practice of which Hurst calls “witchcraft” and “folklore.” As champions of empirical methods and scientific rigor over hunches and suppositions, Hurst and Lentini resemble “Moneyball’s” hero, Billy Beane, who in the movie battles his own scouts’ illogical decision-making.

As several interviewees in “Incendiary” admit, Willingham was not a particularly nice guy (he was given to bouts of temper and one witness says he beat his wife). But consigning a man to death because he’s unlikable, rather than on the basis of hard forensic evidence, is akin to the scouts in “Moneyball” who recruit players based on their jaw lines rather than statistics reflecting base runs and team wins.

Elevating emotions over facts is precisely what Perry does throughout “Incendiary,” when even in the face of overwhelming forensic evidence that Willingham’s case was botched, he simply repeats, “He’s a monster who killed his children,” a phrase designed to override rational thought and go straight to listeners’ (and voters’) deepest fears. But even if Perry’s performance in “Incendiary” is disquieting, as a portrait of the executive leader in action, the film bucks a regrettable trend in political documentaries of late. Too many have been content to rely on feelings about their subjects rather than dispassionate scrutiny of their records.

In “The Undefeated,” which appeared on video-on-demand this month after a desultory theatrical run, talking head after talking head appears on-screen, extolling the virtues of former Alaska governor and Republican vice presidential candidate Sarah Palin. The film — made by Stephen K. Bannon in part to rev up support for a Palin presidential bid — correctly critiques the viciously sexist attacks on its subject during the 2008 campaign. But rather than providing a balanced assessment of her record and qualifications, it instead stokes the passions and predilections of Palinistas everywhere, eschewing bland but healthy objectivity for more toothsome — and partisan — red meat.

Nick Broomfield’s snarky “Sarah Palin: You Betcha!,” which recently premiered at the Toronto International Film Festival, does the same thing for Palin’s detractors, offering up several of her Wasilla, Alaska, neighbors who testify to her petty vindictiveness, but providing little by way of fair, cool-headed reflection or policy analysis. (Also in Toronto was “The Education of Auma Obama,” an earnest but narratively wobbly profile of Barack Obama’s half-sister in Kenya, whose warmth and achievements in economic-development activism are doubtlessly admirable, but they serve as a thin excuse for showing her home movies of a young Barack visiting his ancestral homeland.)

Thanks to Mims and Bailey’s scrupulous attention to fact and detail, “Incendiary” doesn’t need to rely on the emotion-laden testimony of friends, enemies or family members to deliver a vivid portrait of Perry, whose disdain for forensics in the Willingham case will be seen by most viewers as of a piece with his skeptical stance on climate science and evolution. More startling by far, considering Perry’s folksy, aw-shucks style on the stump, is what “Incendiary” shows about his willingness to play rough, especially when his political fortunes hang in the balance.

In 2009, the Texas Forensic Science Commission, which had been formed to review a slew of mishandled criminal investigations throughout the state, was on the verge of hearing damning testimony regarding the Willingham investigation when Perry — in the midst of the campaign for his third term as governor — suddenly replaced three members of the board. Its new chair, a steely former prosecutor named John Bradley, cuts a formidable figure as Perry’s enforcer throughout “Incendiary,” slow-walking progress on the Willingham case, stonewalling the press and craftily out-maneuvering Texas’s open-meetings laws. (Would that Perry had had his own Billy Beane to champion the facts rather than the pugnacious Bradley, whom the Texas legislature later declined to re-appoint to the post.)

As a riveting documentary in the tradition of “The Thin Blue Line” and “Paradise Lost,” “Incendiary” grabs viewers by their throats until the end — which in this case is all the more bitter for being so vague (none of the procedures that would have vindicated Willingham or clarified his case have been satisfactorily concluded).

But this superbly crafted film is even more important in showing how Perry’s dismissal of scientific fact — whether his belief that climate science isn’t “settled” or that schoolchildren can decide for themselves whether creationism and evolution is correct — isn’t just a matter of rhetoric but carries real, life-and-death consequences. What makes “Incendiary” so valuable, both as a real-life crime thriller and political portraiture, is that — its title notwithstanding — it sheds far more light than heat.

The Willingham Case

(104 minutes, at Landmark’s E Street Cinema) is unrated. It contains adult themes. Filmmakers Steve Mims and Joe Bailey, Jr. will answer questions after the 7:15 and 9:45 p.m. screenings Friday and Saturday.