It might not have been very punk rock of Green Day's Billie Joe Armstrong to [article id="1690645"]join forces with Christina Aguilera on "The Voice"[/article] -- he'll serve as a "mentor" for her team during the upcoming season -- but when, exactly, was the last time Billie Joe Armstrong cared about being punk rock anyway?

It certainly hasn't been any point over the past, oh, 15 years or so. Ever since 1997's Nimrod album, he's been on a different trajectory, growing as a songwriter and a musician, embracing stuff beyond punk's three-chord bluster (Bob Dylan, Petula Clark, Kiss) and creating songs like the '90s prom anthem "Good Riddance (Time of Your Life)" and the somber "Wake Me Up When September Ends." He's written not one but two concept albums, [article id="1543888"]recorded a song with U2[/article], morphed Green Day's live shows into certified [article id="1645332"]arena-rock spectacles[/article] and even [article id="1649041"]starred on Broadway[/article].

None of those things could even charitably be described as punk rock (aside from American Idiot's vivisection of the G.W. Bush era, of course), and from the sound of things, Armstrong and Green Day are moving even further away from their roots on the upcoming [article id="1689928"]¡Uno! ¡Dos! ¡Tre![/article] trilogy. That's not necessarily a bad thing, either. After all, what's the point of painting one's self into a corner, especially when you haven't been welcome in that corner since "Longview" first showed up on MTV in 1994?

So, it wasn't exactly surprising that Armstrong said yes to "The Voice" -- in a statement, he said he did it, in part, because his family are fans of the show -- nor was it surprising that some of his fans responded to the news by calling him a "sellout." That's been the reaction for nearly as long as Armstrong's dared to step out of the punk-rock box after all, a predictably knee-jerk damnation that, while rooted in noble intentions, seems positively antiquated these days.

I mean, is it even possible to sell out anymore, when bands line up to provide soundtracks to iPhone ads, and every tour is sponsored by a beverage/wireless provider/car manufacturer? Given the general disappearance of music videos from the airwaves (guilty as charged), the steady decline of record labels and the continued fracturing of radio, selling out is basically part of the business model these days. Wail all you want, that's not gonna change anytime soon, either (and for the record, one has to wonder if these same "fans" cursing Armstrong for selling out have been paying attention to anything his band has done over the past decade).

To that end, I get the feeling Armstrong probably realized the inherent ridiculousness in being called a "sellout" just after Dookie went supernova, so he's probably not losing any sleep over this latest round of accusations. And while he's not exactly a sneering, snotty punk rocker anymore (I don't know him personally, so it's entirely possible he does his sneering and snotting in private), a part of me wants to believe that his joining "The Voice" might also be the most punk rock thing he's done in years. Whether he knows it or not, he now has a chance to become the most subversive person on network TV, a tattooed mischief-maker who strongly urges contestants to sing Dead Kennedys songs and occasionally makes a Mitt Romney joke. At the very least, maybe he'll drop an f-bomb on live TV. You know, good stuff like that.

Then again, it's entirely possible Armstrong will just play it straight. Either way, I'm not about to bury him just because he signed on for a televised singing competition. Maybe he wants to use the platform to promote the new Green Day albums or get his kids backstage passes to meet Blake Shelton, or perhaps he's devising a devious plan to burn the whole thing to the ground. Shoot, maybe he was just bored. You can't teach an old punk new tricks, but when that old punk hasn't been punk since the Clinton administration, I suppose anything is possible. And Billie Joe Armstrong on "The Voice" is proof of that point. Like it or not.