Actor Heath Ledger portrays the Joker as a humourless psychopath in Batman: The Dark Knight. (Warner Bros. Pictures)

A promotional poster for Christopher Nolan’s blockbuster The Dark Knight shows Heath Ledger’s terrifying Joker behind a pane of glass, scrawling the phrase “Why so serious?” in what looks to be blood. It’s meant ironically, of course, the morbid humour of a murderous psychopath who finds profundity and good clean fun in terrorizing an entire city.

This macabre interpretation of the famous comic-book villain, and the personal toll it seemed to have taken on its star, is the film’s main draw, the reason it’s breaking box-office records with grim conviction. It poses the question: Why so serious, indeed?

By contrast, the Joker of the 1940s, in Batman comic’s earliest issues, was a playful counterweight to Bruce Wayne’s square-jawed heroics. He was a nemesis and foil whose schemes often verged on slapstick. They centred on sputtering Rube Goldberg devices and clumsy ploys to lure Batman into his clutches — and they failed with the comical regularity of a puppy chasing its tail. Cesar Romero’s Joker in the campy ’60s television show was just as plainly a clown; Ronald McDonald with ambition. Hair dyed an unconvincing lime and leathery wrinkles plain to see beneath his pancake makeup, he was merely another buffoon on a program that took the “comic” intent of its source material to heart. Even Jack Nicholson, who has minted a career portraying hams with sinister grins, plied his lunacy with a wink in Tim Burton’s 1989 movie Batman.

Cesar Romero's version of the Joker in the Batman TV series was a campy character. (Courtesy 20th Century Fox)

Heath Ledger’s Joker, however, is something different. He is dark and cruel and violently insane. His broad smile isn’t a huckster’s gimmick or a plastic prosthetic, but scar tissue from slits he has carved into his own cheeks. Ledger’s accidental death after the filming adds a grisly pall of gravitas to the act. The performance is already being touted for an Oscar. This is clearly no cartoon.

Comic-book writers through the years have variously rendered the Joker as something between a callous murderer and cackling pest. Nolan’s new film cribs its depiction from several sources, notably Frank Miller’s operatic 1986 comic Batman: The Dark Knight Returns, whose Joker was gritty and nuanced. Heath Ledger’s version is unique for what it adds — namely the weight of the Sept. 11 attacks.

Critics are fond of placing comic-book characters in the pantheon of ancient myths, supersized symbols of our failings and desires. Transposed in live action onto the movie screen, they’re expected to function as metaphors; thus, the X-Men become crusaders for gay rights, Spider-Man’s web the sticky substance of an adolescent’s sexual awakening. And the Joker — he’s now a proxy for the terrorists at our door: brutal, unyielding, motivated by a personal code that’s unfathomable to his innocent victims and the forces allied to protect them. Ledger’s Joker is al-Qaeda and the Taliban, the entire spectre of extremism, in fact (minus the religious element). He straps himself with explosives, sends footage of hostages he’s tortured to news networks. He scoffs at death — the death of his victims along with his own. Some in the film even call him a terrorist, in case the audience had any lingering doubts.

Jack Nicholson's version of the Joker made full use of the actor's trademark sneer. (Courtesy Warner Bros. Home Video)

Ledger handles the baggage with chilling aplomb, but there’s something lost by subsuming the Joker into America’s war on terror. It all but erases the memory of a character who, after all, was invented for kids. Batman, the Joker — the whole loony ensemble — were designed to thrill innocent minds. The tales were a frothy mix of adventure and suspense, as light and colourful as an ice-cream float. The sublimation they provided was simple: vicarious power (the muscles, the morality) and success. Whatever the obstacle or the villain’s dastardly design, the hero would prevail; a touching, if specious, vision of adulthood. The fact that reality rarely turned out this way was a lesson absorbed long after such characters were dropped as surrogate mentors.

With his garish suits and unfettered flamboyance, the old Joker was just plain silly. His fastidious plans consistently foiled, he was tragic only insofar as he never seemed to catch on. But the tragedy of this new Joker runs right off the screen, into the chaos of our new century and the premature death of a promising young actor. It’s a heavy weight for any character to bear, let alone one founded in childhood escapism. Comic books and their outlandish cast were meant to be antidotes to reality. Today they echo it: The knight is dark, and the Joker isn’t joking.

Batman: The Dark Knight is in theatres now.

Guy Leshinski is a writer based in Toronto.