The careers of Jon Favreau and Vince Vaughn have seemed inexorably linked since the breakthrough success of Swingers, their hipster comedy about wannabe actors braving the L.A. social scene. Since becoming close friends on the set of 1993’s Rudy, the pair has collaborated on Made, a bruising comedy about ex-boxers finding their way in the world of organized crime, and later The Break-Up, in which Vaughn starred and Favreau moonlighted as a sage bartender.

Four years ago, Favreau directed Elf, a minor holiday classic about a grown man, raised by Santa’s little helpers, whose North Pole upbringing leaves him woefully unprepared for the manic intensity of New York City. Now, not to be outdone, Vaughn stars in Fred Claus, in which a cynical Chicagoan, who just happens to be St. Nick’s estranged older brother, is whisked away to Santa’s workshop for a crash-course in holiday spirit.

It’s a premise with potential, but director David Dobkin (Wedding Crashers) approaches it clumsily, failing to strike a comfortable balance between farce and mawkish sentimentality. Rather than creating imaginative situations for Vaughn to explore, he merely asks that Vaughn be himself, as if his personality were big enough to wring humor out of a comic vacuum.

Sometimes, it is. As one might expect, Fred is slick and brazenly disingenuous, a fast-talking con man who has been living in his brother’s ever-expanding shadow for more than 1,500 years. (More on this later.) His dream, to build a gaming room across the street from the Windy City stock exchange, requires a $50,000 investment. When his latest get-rich-quick scheme lands him in jail, he dials Santa (Paul Giamatti) for bail and a loan.

Santa is hard-pressed to say no -- altruism, after all, is his specialty -- so the brothers strike a deal: Fred will work for the money at Santa’s North Pole compound, helping his elves prepare for their most daunting Christmas ever. Their workshop, normally a bastion of yuletide cheer, has fallen under the watchful eye of a Grinch-like efficiency expert (Kevin Spacey) bent on shutting down the holiday for good.

Why? Who knows? For that matter, if Santa is the younger sibling, how has Fred managed to defy the aging process while his brother enters his twilight years? And why, if Fred has been wandering the earth for more than a millennium, does he seem so much like a product of modern-day Chicago?

Fred, who seems thoroughly immersed in contemporary culture, rarely alludes to his past, which might have made his character something more than a one-note misanthrope. But what more is to be expected from a movie that can’t think of anything better to do with Santa’s elves than have them attack the towering Vaughn, Lilliputian-style, not once but twice? Ho, ho, ho, indeed.

There are some funny moments, including Fred’s visit to Siblings Anonymous, where he endures absurd testimonials from the likes of Frank Stallone, Roger Clinton and Stephen Baldwin. And the cast – from Vaughn and Giamatti to Kathy Bates and Rachel Weisz – is far stronger than the material, which goes too often for the most obvious laughs before turning on the calculated Christmastime charm. In the end, Fred Claus is a bright premise squandered by filmmakers eager to please but not quite up to the task.