Starring Rachel Weisz. Rated PG

Denial is a somewhat plodding, fact-based tale with few transcendent moments in acting or staging that still manages to be oddly satisfying in the end.

The title refers to a key subject for historian and professor Deborah Lipstadt, an American (of Canadian and German background) who turned her attention in the 1990s to a growing corps of Nazi sympathizers then attempting to claw back the proven record of the Shoah. Only briefly mentioned in her Denying the Holocaust, British author David Ir­ving sued Lipstadt and her Penguin publishers for libel, exploiting a British law in which the defendant bears the burden of proof.

Irving, a self-taught researcher who got cozy with aging ex-Nazis while writing semireputable military his­tories of the Second World War, later met with infamous shitheels like Ernst Zündel, Fred Leuchter, and our own Doug Christie. Here, the oily Irving is portrayed by Mike Leigh favourite Timothy Spall, who usually plays sympathetic, working-class characters (in Mr. Turner, for example).

Much in the manner of Brexit-er Nigel Farage, Irving, as the film avers, has nursed lifelong resentments at being excluded from Britain’s old boys’ club. He also looks less like Spall and more like Tom Wilkinson, though the latter is already engaged here as the American’s chief counsel.

The real-life Lipstadt certainly doesn’t resemble glamorous Rachel Weisz—she’s more of an Imelda Staunton type who’s actually the same age as the codgerly Irving. The reliable Brit does her best, but seems hemmed in by the character’s Cyndi Lauper–like accent—even more so by the fact that, given the peculiar strategy of the trial, which concluded in 2000, Lipstadt had virtually nothing to do.

The screenplay by playwright David Hare, therefore, has to work in various middling subplots to overcome dramatic inertia. (His asides about sexism inherent to the case are notably relevant.) And veteran director Mick Jackson—who made L.A. Story and The Bodyguard within a year of each other—struggles to find ways to open this cloistered story.

The cloister is where this story belongs, however. As the larger events of the past recede, only language keeps their meanings alive. This workmanlike movie is no thriller, but it respectfully encourages viewers to explore the moral weight of history through the arguments of today. In that sense, its value can’t be denied.