One would have thought that “Casablanca” had suffered enough indignity when it was turned into a TV series with David Soul playing Rick Blaine a quarter-century ago. But now the memory of the 1942 classic is tarnished further by “Allied,” a cornball, cliché-ridden World War II romance that mimics many of its beats on a much larger scale and succumbs to cinematic elephantitis of a nearly risible sort. It brings together an impressive array of ingredients—an extravagant physical production (designed by Gary Freeman), carefully-manufactured costumes (by Joanna Johnston), luxurious widescreen cinematography (by Don Burgess), a lush score (by Alan Silvestri) and charismatic leads—but the result proves a cinematic molehill, thanks to Steven Knight’s feeble script, Robert Zemeckis’ turgid direction, and a lack of chemistry between the stars.

Brad Pitt, returning to the war against Nazism once more, is Max Vatan, a Canadian officer serving with British intelligence in London, who’s parachuted into the Moroccan desert in 1942. His mission is to proceed to Casablanca and connect with Marianne Beausejour (Marion Cotillard), a stalwart member of the French resistance, who has escaped capture in Paris and made her way to North Africa, where she has ingratiated herself among high society in the Vichy-controlled city. He will pose as her loving husband, a chemicals manufacturer, and together they will finagle an invitation from Nazi officer Hobar (August Diehl) to a gala reception for the German ambassador, using the event to assassinate him.

The plan succeeds perfectly, but in preparing for it the two become romantically involved; the culmination of their affair is a ludicrous roll-about in a jeep that’s engulfed in a swirling sandstorm meant to mirror their boiling passion. One has to take their emotional connection pretty much on faith, however, because Pitt’s stiffness and Cotillard’s icy demeanor don’t demonstrate much feeling of any sort. They seem more devoted to showing off their perfectly-assembled wardrobes than exhibiting any dramatic urgency, coming across like models on a runway rather than actual human beings involved in risky military operations or falling in love.

Still, Vatan arranges for Marianne to come to England, and before long they’re married and spoiling their first child, a cute-as-a-button daughter. But before long danger appears on the horizon—not just in the form of Nazi planes engaged in the Blitz, but of suspicions that arise when it’s discovered that military secrets are somehow being passed to the Germans. Vatan will become involved in efforts to unmask the possible traitor, and they take him into danger once again.

It would be unfair to reveal too many of the details of this second half of “Allied,” but suffice it to say that there are echoes of Hitchcock here. Unfortunately, they are played out in such a flatfooted fashion that you’re likely to be reminded not of “Foreign Correspondent,” “Saboteur” or “Notorious” but of the missteps of his later years like “Torn Curtain” and “Topaz.”

During this latter part of “Allied,” Pitt perks up somewhat, but Cotillard remains surprisingly impassive, and the supporting cast has little opportunity to shine. Simon McBurney makes what he can of his single scene as a self-described S.O.E. “ratcatcher,” but the others— including Lizzy Caplan as Max’s lesbian sister, Matthew Goode as a badly injured vet, Anton Lesser as a mysterious jeweler, Josh Dylan as a nervous pilot and Thierry Fremont as a French resistance fighter—barely register. Worst of all is Jared Harris as Max’s stiff-upper-lip superior, who has the unenviable task of delivering a final order that Knight and Zemeckis apparently believe might have the same memorable impact as “Round up the usual suspects.” Let’s just say that Harris is no Claude Rains, but it’s not his fault the line is so lame.

It’s not impossible to revisit the tropes of World War II movies successfully—Pitt himself did so recently, seriously in “Fury” and with tongue-in-cheek in “Inglourious Basterds.” But the stuffy, stilted, lumbering “Allied” earns a place beside David Selzer’s similarly overblown “Shining Through” (1992) among misguided big-budget attempts to go back to the front.