The number one song in America is a rock tune. This isn’t as atavistic as a silent movie winning Best Picture at the Academy Awards. But in Chartland, where pop princesses and rap royalty reign, rock just hasn’t been part of the ruling class for some time. For the past five weeks at least, rock has ruled again.

“We Are Young” by the band fun. — as in lower-case “fun” period — is the first rock ‘n’ roll song to top the Billboard Hot 100 since the summer of 2008, when Coldplay’s “Viva la Vida” became the 999th number-one song of the rock ‘n’ roll era. Those are the only two rock songs of the last decade to claim the top spot. To put this in perspective, Adele, LMFAO, Rihanna, and Katy Perry have each spent considerably more time atop the singles chart over the last year than have all rock acts combined over the last decade.

Many purists might point out that the situation is even worse than the recent chart drought indicates. Neither “We Are Young” nor “Viva la Vida” is rock ‘n’ roll in any Chuck Berry sense. Who stole their guitars? The musical taxonomy perhaps owes more to what they are not (teeny-bop pop, rap, country, R&B) than to what they are, which is harder to pin down.

To be sure, a top-charting single has never really been the measuring stick of the guitar-bass-drums set. Neither Led Zeppelin nor The Who scored a number one hit in the U.S. But acts as diverse as The Edgar Winter Group, Fine Young Cannibals, Guns N’ Roses, EMF, The Box Tops, Simple Minds, and Don McLean all found number one without really looking for it.

Number one used to look for rock. Now it couldn’t find it with a search party.

But fun. somehow stumbled upon numero uno. The bestselling song of 2012 is upbeat and uplifting. Singer Nate Ruess does Lindsey Buckingham impersonating Freddie Mercury. The main instrument here is his theatrical voice. “We Are Young” is a soaring, sing-songy mantra: “Tonight, we are young/so let’s set the world on fire/we can burn brighter/than the sun.” If you didn’t initially catch this infectious ode to youth, it comes around again five times in a multi-tracked vocal accompanied by a monotonous beat and a reiteration of a single piano chord. Instead of boring, repetition becomes a habit.

The most recent rock ‘n’ roll single to claim the highest spot on the charts has much in common with rock ‘n’ roll’s first number-one hit. Whereas Bill Haley pledges to “rock ’til the broad daylight,” fun. boasts of drinking to last call. Both understand their mission as supplying the soundtrack for the springtime of life. When Bill Haley and the Comets conquered the charts with “Rock Around the Clock” for eight weeks in the summer of 1955, they did so after a slow climb that began the previous year as a b-side. Similarly, fun. released “We Are Young” in September of 2011 only to reach number one in March 2012. Radio, the catalyst for most hits, proved a latecomer for both tunes. The television program Glee and a one-minute Chevrolet Super Bowl commercial catapulted “We Are Young” into public consciousness. The movie Blackboard Jungle did the trick for “Rock Around the Clock.”

Something went wrong for rock somewhere between “Rock Around the Clock” and “We Are Young.” Rock stars morphed from supernovas to red dwarfs. The genre became lyrically opaque, sonically dour, and stylistically inconspicuous. In a single generation, rock evolved from Elvis in sequins to Cobain in flannel, from Roger Daltrey swinging a microphone to Eddie Vedder staring at his shoes, from McCartney singing silly love songs to Morrissey sobbing that last night he dreamt that somebody loved him. The phrase “alternative rock” became a redundancy, as it pushed rock itself outside of the mainstream. The more seriously they took themselves the less seriously the public took them.

The success of “We Are Young,” coming within a genre that perversely now views success as a failure, may prove rock music’s last gasp as popular music. The rock acts looking down at number one from below play dark, depressing, uninspiring, inaccessible music that you can drink but not dance to. That’s just not fun.