The thing I couldn’t quite figure out about Nora Ephron’s new film version of “Bewitched” was why Nicole Kidman as the pretty suburban witch took as her model not the savvy but sly Elizabeth Montgomery of the original television series but a breathless, wide-eyed innocent of the sort that Marilyn Monroe used to specialize in.

Surely if being a witch, even a television witch, means anything, it must mean being really smart rather than really dumb?

But in Ms. Kidman’s conception of the part, her superpowers are not learned from years of poring over books of spells or hermetic literature. Instead, they are an uncovenanted gift, like Marilyn’s naughty-child sexuality. Like it, too, they are at least as much of a nuisance to her as they are a means of getting what she wants.

But that still doesn’t explain why she wants to renounce them, or why Darren (Will Ferrell) is shocked and offended by them instead of thinking them cool.

Back in the days of the TV series (1964-72), there was a good reason, understood by everyone, why Ms. Montgomery’s Samantha was forbidden by Darren from practicing witchcraft, and why she pretended to submit to his prohibition. It was widely supposed then that a husband needed to feel he was king in his castle, that the power in the relationship belonged to him. A woman with the power not only to take care of herself but to alter reality at the twitch of a nose could hardly fit comfortably into the then-desirable role of the submissive wife.

Yet “Bewitched” the television series did as much as anything in American popular culture to alter these archaic assumptions about marriage. Samantha never really sacrificed her powers for Darren and domesticity, and the poor chump himself could hardly have been unaware of the fact. He was a pathetic wittol in the case of his wife’s infidelity with the always comic dark powers.

Thus the show took on an archetypal quality, like “The Honeymooners” only more so. For as feminist scholars have since reminded us, historical associations of women with witchcraft are all bound up with the masculine fear of women’s power. Samantha Stevens was a sanitized but still powerful emblem of those dark and long mistrusted powers at the dawn of a new feminist day.

All this is missing from the new movie. Where the lineage of the television series ran, however circuitously, back to the “Malleus Maleficarum” or “Hammer of Witchcraft” of the 15th century, that of the film goes no further than to the comic-book superhero and connects to nothing more interesting or culturally resonant than the adolescent power fantasies that have become Hollywood’s stock-in-trade in the post-revolutionary era.

That must be one reason for Ms. Kidman’s innocence, which extends even to this witch’s delighted admiration for the witchcraft of microwaves and automatic sprinklers. In spite of Michael Caine’s droll turn as her father, we don’t know where she’s been up until now – though we do know she has been kept away from the normal amenities of modern life, popular vulgarisms, and even forbidden to watch the television show “Bewitched.” In other words, Ms. Kidman’s Samantha hails from the same Never Never Land or Planet Krypton as all comic superheroes.

Or at least the ones with superpowers. As the recent “Batman Begins” reminds us, the man who must rely on knowledge and technique rather than super strength or trans-specific powers to defeat his foes has his beginnings in a terrible knowledge. Surely, you would think, there must be a better model for a witch than the alien or mutant innocents of the comics?

But then that might risk striking a serious note that the movie clearly could not sustain. Though the writing, by Ms. Ephron, her sister Delia, and Adam McKay, is often sprightly and the jokes mostly better than those in the recent and disappointing “Honeymooners,” the triviality of the whole conceit overwhelms the film. And Will Ferrell’s presence unbalances it in another way.

Ms. Ephron’s big idea for a framing device is to have some network suits remaking the television series and offering the part of Darren to one Jack Wyatt (Mr. Ferrell), supposedly a big movie star who has had a couple of big flops. Wyatt condescends to take the part in a mere television show on the understanding that he is to be the center of interest while the witchy wife, for whom he wants to cast an unknown, has barely a speaking role.

The unknown, unbeknownst to him, turns out to be a real – or rather a “real” – witch. Think of the comic possibilities!

But hang on a minute. Is it remotely plausible in any conceivable universe that even Jack Wyatt, obviously not the brightest bulb on the marquee, could imagine Darren as the star of “Bewitched”? As he himself puts it: “I’m Darren? They replaced Darren in the original series and no one noticed!”

Yet the film tries to get away with exactly the same impossibility, pouring Mr. Ferrell’s energetic mugging and over-the-top physical comedy into the mold of that inevitable nonentity, Darren Stevens, just because he is a big star who can “open” a movie.

His need to treat “Bewitched” as a vehicle for what seems, to me at least, his mostly unfunny clowning is the main reason for the film’s lack of movie witchcraft. It’s also responsible for the stunning irony of Miss Kidman’s reconversion of an icon of feminist power into one of submissive femininity.