As I'm writing this I'm watching American Idol. I've been a regular Idol watcher for some time now, and am unembarrassed about it. It's a fascinating exercise in establishing what the mainstream of American popular music is understood to be, and shaping some very raw talent to fit the production standards of the music industry in its most blatantly commercial manifestation. I rarely like the music that's sung on the show, but it's really not a show about music per se, it's a show about cultural production.

Or at least that's how I justify my interest in it.

But tonight's episode is a trip because it's a full-on rock episode. Slash (!) is the guest mentor, and the first song performed this evening was Adam Lambert - he of the ridiculous high range that he likes to show off every chance he can get - doing a pretty decent version of Led Zeppelin's "Whole Lotta Love." Apparently this was the first time that a Zeppelin song has ever been done on American Idol, and it didn't completely suck. It was followed by Allison Iraheta - the only female singer left in the final four - who did an okay-not-great version of Janis Joplin's "Cry, Baby" (which they kept referring to as though it was "Cry Baby," so not the connotation of the song's lyric).

Idol has always had a strangely ambivalent relationship to "rock." I didn't watch the show much in the first few seasons, and part of the reason why was that its version of "pop" was pretty clearly non-rock, sweet vocal ballads and modern R&B having been the main idioms at first, neither of which get my mojo working. That began to change in season 4 (I had to look this up on Wikipedia) when Bo Bice, a "southern rocker" who was fairly lightweight as rockers go but had a decent bluesy rock voice, made it to the final two, only to lose to country singer Carrie Underwood. Since then the rock quotient has grown modestly but steadily, with the biggest breakout of course coming from Chris Daughtry in season 5, who made it to the top 4, was unceremoniously booted but then had a bigger album by far than any of his competitors. Last year, David Cook won with a sound markedly similar to Daughtry, and this year two of the final four (the aforementioned Adam and Alison) seem to be as much "rock" as anything else, stylistically.

What I find fascinating about all this is how the show, even as it absorbs rock more and more into its fabric, still maintains a significant element of the "rock" vs. "pop" binary - as though rock were not just another version of pop rather than its antithesis. Of course, rock fans have long had much invested in this binary, since it upholds their belief that rock is something of greater value than pop, more authentic, more real (Simon Frith, one of the founders of academic popular music studies, has spent much of his career analyzing these distinctions). But the pop industry has usually been quick to absorb the rebellious veneer of rock every chance it can get. That American Idol has often been more cautious in its approach to rock is, far as I can figure, the result of two factors:

1. It's on TV, which means it has to shoot for a more conservative notion of "mainstream" than, say, Top 40 radio, because TV as a medium (or at least, network TV) has always been defined by a decidedly middle American version of the mainstream.

2. The show began in the era of the high-gloss super-manufactured likes of Britney Spears, Backstreet Boys and N'Sync, and its initial target audience - I gather - was the young audiences of those artists, for whom rock was deemed too "edgy." As those artists have lost much of their luster (Justin Timberlake excepted since he completely reinvented himself), Idol has redefined its own sense of the mainstream by incorporating more and more rock into its fabric.

Of course there are still limits to all of this. The decidedly non-rock Danny Gokey, another of this season's final four and one of the clear favorites, just murdered a version of Aerosmith's "Dream on." Not all artists can do rock well and American Idol still needs folks like Gokey to appeal to its non-rock fan demographic, which is almost certainly still a bigger part of its audience than its rock fan contingent.

And, strangely, rap music is still largely beyond the pale of Idol even though there's no doubt that in strictly commercial terms it's been the biggest thing going for the past 15 years (since Kurt Cobain died). I'd need a whole other post to try to make sense of that.