The song's message is a tricky one: girlfriend's just split from her no-good man and is out celebrating with her crew. She's snaring a new man, but her old one is watching, and the song is directed to him.

"If you like it then you should have put a ring on it," goes the singsong hook, and eventually, the lyrics reveal that this is what the singer really wants: for her guy to make like a prince and grab her, delivering her to "a destiny, to infinity and beyond."

That's corny, and Beyoncé's not one for cheap sentiment. No matter what the bridge says, it's that chorus that wins the day, and it is a slap in the face of a man who's already blown it. Prince Charming is left standing there like the second lead in a romantic comedy, while Beyoncé lets her new guy -- and the beat, and those jumping background singers -- sweep her off her feet.

"If I Were a Boy" mines a very different mood, and in doing so, elevates Beyoncé's game even higher. This is her Streisand moment -- a tender, fairly simple ballad that Beyoncé uses to prove she's a great vocal actress.

Co-written by Toby Gad, a longtime ingenue supporter who gave Fergie her Song of the Year with "Big Girls Don't Cry," this tearjerker is circular in structure, its unending cadences suggesting that the problem B's addressing is eternal. This isn't just another breakup song; it's an elegy for female empowerment, Beyoncé's admission that no amount of money, fame or skill can solve the basic inequity between her man's heart and her own.

The lyric starts out with Beyoncé musing about all she'd do if she could be anatomically and hormonally altered: eschew grooming, embrace booze, dog after every lady in sight. Cute, and at this point a smile underlies her delivery. But then she hits her upper register, and the sorry sneaks in: She's dreaming that if she were a boy, if a man could have a woman's sense of empathy, things would be different.

By the second verse, she sounds resigned, ticking off more cruelties that male empowerment allows. "I'd put myself first," she mutters. But she can't -- she returns to the chorus, and her imploring vision of life as (with?) a "better man."

Then the script flips. No more dreaming. Addressing her straying lover directly, she says it's just too late. Her tone is gentle, open: Instead of the snap of "Single Ladies" and "Irreplaceable," there's real sadness as she shuts this door.

The last verse is just slightly stagy, with a sneer sneaking in as she sings, "But you're just a boy." In the end, Beyoncé can't resist arching her eyebrow; she's a survivor, and she won't let her pain completely unmake her.

But that's the final, poignant point of this excellent song. In Beyoncé's world view, an independent woman must sacrifice the princess fantasy she was sold as a child, and keep that steely edge, even when her world is melting around her. The compassion Beyoncé's vocal conveys as "If I Were a Boy" concludes is as much for the man who can't fulfill romance's impossible dream as it is for herself.

Post-feminist independence is usually staged as a comedy -- chick lit, "Sex and the City," "Irreplaceable." Here, Beyoncé turns it into an adult drama, and lets it bleed. It's a powerful and complex view of sexual politics from a singer and songwriter who's truly come into her own.

-- Ann Powers

Photo of Beyoncé performing with Justin Timberlake in September by Jeff Christensen/Associated Press