Heath Ledger is currently giving an uncommonly soulful performance as a lovelorn gay cowboy in ''Brokeback Mountain." The only reason to sneak from that movie into ''Casanova," Ledger's other holiday picture, is to confirm that he hasn't lost his ability to smile, or his appetite for women.
With that settled, you should feel free to head back to the heartbreak of ''Brokeback" and avoid the dopiness afoot here.
Ledger is not playing just any cad. He's playing, to paraphrase Elizabeth Taylor in ''Butterfield 8," the slut of all time -- or at least of 18th-century Europe. Unfortunately, ''Casanova" is not a sex flick or even a plausible romance. It's a cartoon.
In his day (he died at 73 in 1798), Casanova was a soldier, clergyman, memoirist, aristocrat, ex-con, and spy. He played the violin and brought the lottery to Paris.
Ledger brings a terrific blend of slyness and virility to the role of an unstoppable, bewigged libertine whose conquests include an entire nunnery. Notoriety gets him into hot holy water with the Catholic Church. If he doesn't find a respectable wife, he'll be expelled from Venice.
So he and his manservant, Lupo (Omid Djalili), scour the city for a suitable bride and find Victoria (Natalie Dormer), a milky virgin who can't wait for Casanova to deflower her. Of course, the male virgin across the way, Giovanni (Charlie Cox), thinks he called ''shotgun" first and proceeds, in a rare amusing scene, to give Casanova a jealous slap with a glove.
Conveniently, it's Giovanni's sister, Francesca, who has truly caught Casanova's fancy. She's an outspoken intellectual and huge fan of a best-selling writer banned for feminist ideas. Francesca is played with occasional brio by Sienna Miller, an actress more famous for enduring the indiscretions of her real-life Casanova, Jude Law.
Casanova would have his conquest were Francesca not already engaged to a rich stranger -- a lard magnate fresh off the boat from Genoa and played by Oliver Platt. He's the movie's only genuine surprise: mild-mannered, effeminate, and big enough to participate in the Macy's Thanksgiving Day Parade.
Casanova winds up juggling several false identities and two women, all while avoiding the sniveling Vatican inquisitor (Jeremy Irons, in a hideous wig) who's arrived to prosecute, then execute, ''moral heretics."
While it purports to celebrate free thinking, ''Casanova" is woefully lacking sensuality or, for that matter, sex. Director Lasse Hallström and his screenwriters take a relentlessly adolescent approach to their subject. One scene, in which Victoria teases Casanova from under a table, suggests ''Benny Hill" on the WB.
The movie treats trysting as comedy and yet is stingy with the laughs. An action-packed life is now the chaste story of a rake whose romantic reformation is supposed to make us swoon. Must love dog? No thanks.
Wesley Morris can be reached at email@example.com.