As South Park begins its 12th season this week, the cartoon series about the wild adventures of Colorado fourth-graders has never been less culturally relevant. The creation of writer-director Trey Parker and producer Matt Stone (who between them voice most of the main characters), the story of Stan, Kyle, Cartman and Kenny remains one of the most popular shows on Comedy Central and Canada's Comedy Network. Yet in a way, its time has passed. When South Park debuted in 1997, based on a short film in which Jesus battled Santa Claus for Christmas supremacy, it became what the New York Times described as the "cranky, obscene voice of 1990s slacker culture," spawning a movie and turning Parker and Stone into superstars. Now it's not even the most influential show on its network; South Park can parody Hillary Clinton but The Daily Show can have her as a guest. But instead of being nostalgic for the time when they were on the edge of pop culture, Stone — who handles most interviews for the team — told Maclean's that he and Parker can barely watch the episodes that made them rich: "They're terrible as far as story structure and missed opportunities for great jokes." If he's right and South Park is better now, it may not matter that it's less consequential.

The odd thing about South Park is that it's most famous for things it doesn't necessarily do best. To casual viewers, South Park is known for the running gag about the muffled-voiced Kenny getting killed every week. But the gag became old very fast, and the creators have mostly dropped it: "He's such a prop," says Stone. "He can't really talk." The show is also known for its political humour; because each episode is produced in a week, it can respond instantly to topical events. But Parker has said his best scripts are the ones that focus less on messages and more on "boys being boys." The most popular recent episodes have been almost apolitical: the show won an Emmy last year for a send-up of the video game World of Warcraft, and followed it up with a show about Guitar Hero. South Park still has lots of scatological humour, but much of it is an exaggerated way of making the audience, in Stone's words," kind of remember what it was like to be eight years old."

South Park doesn't have much choice but to emphasize its non-topical side; it's burned through two chances to be a true cultural force. Its late-'90s supremacy was brought to an end when Sacha Baron Cohen's Borat and Fox's Family Guy outdid South Park's racist, obnoxious Eric Cartman on a higher budget. Early in this decade, it seemed as though South Park was about to become relevant again, as political commentators started pointing to Parker and Stone as the leaders of a political movement. Conservatives praised the show for its attacks on anti-smoking activists and environmentalists, and Brian Anderson, editor of the conservative magazine City Journal, published a book called South Park Conservatives: The Revolt Against Liberal Media Bias.

Parker and Stone were uncomfortable with being pegged as conservative comics; Stone complains that "as soon as something gets popular, it gets co-opted by somebody saying 'that's ours.' " Still, they seemed to run with the idea for several years, amping up the political messages in the show. But events, and changing political trends, caught up with them: by the time their 2004 election episode portrayed voting as a choice between "a giant douche and a turd sandwich," this pox-on-both-your-houses approach was like a relic of the Clinton era when the show began, already dated in the more polarized Bush era. Michael Cust, an editor for the libertarian blog LibertyinCanada.com, adds that while the show still appeals to libertarians like himself, conservatives turned away when they realized that the creators "don't hold conservative moral values." By the time Parker and Stone did an episode attacking the Republicans for their behaviour in the Terri Schiavo controversy, the South Park Republican craze was over.

Since then, there have been individual newsmaking episodes, like a Scientology spoof that led to the departure of South Park voice actor (and Scientologist) Isaac Hayes. But those are one-off occurrences. When Parker and Stone tried to start a controversy in a 2006 episode about censorship and rioting over images of Muhammad, they were chagrined to discover that the only thing that made the headlines was their attack on another animated show, Family Guy.