UPDATE: Jaime J. Weinman notes how Stephen Colbert’s presidential campaign proves Maclean’s “wacky sitcom” theory.

A few months ago, Oshawa, Ont., Mayor John Gray found a way to raise his city's profile: pick a fight with a comedian pretending to be a TV pundit. Stephen Colbert, who plays a bear-phobic right-wing opinion journalist on The Colbert Report, had done a segment castigating Oshawa for its annual Teddy Bear Toss, and Gray realized he could turn this into a repeat appearance. "I said, hey, why don't we just issue a challenge here?" Gray told Maclean's. That's how Colbert wound up doing a full-fledged story arc about the hockey feud between the Oshawa Generals and the Colbert-backed Saginaw Spirit, "with their inspirational mascot Steagle Colbeagle the Eagle." Welcome to the evolution of The Colbert Report, which celebrates its two-year anniversary on Oct. 17. What started as a spinoff from The Daily Show has turned into a wacky sitcom.

When The Colbert Report began, the biggest question was whether the writers could possibly sustain the format they had chosen. The Daily Show has a group of comedians to back up host Jon Stewart; that group may not be as strong now that Colbert is gone, but Stewart doesn't have to do it alone. The Colbert Report has no regular supporting cast at all; like the Fox News and MSNBC shows it's parodying, it's a one-man operation. Except for interviews, the regular segments have Colbert alone at his desk, playing the perpetually enraged pontificator. Reviewing the show's premiere, Brian Lowry of Variety pointed out that "the more confining format makes it more difficult to regularly generate laughs."

Instead, the show has managed to generate two years' worth of good ratings for Comedy Central in the U.S. and CTV in Canada. A sign of its success is its current run of tie-ins and promotions: this week sees the release of Colbert's book, I Am America(and So Can You!), written entirely in character, while the show just announced the elevation of head writer Allison Silverman to the rank of executive producer. Silverman told the radio podcast "The Sound of Young America" that the show appealed to her because it's "about news, and satirical, but also with somewhat of a sketch element that's character-based." It's the character element that has taken over and made the show successful -- even to the point of crowding out the satire.

The early episodes of The Colbert Report introduced some ongoing topics for Colbert to obsess over, such as his fear of bears(he usually identifies them as "the No. 1 threat to America!"). But as the series has gone on, it's come to depend so heavily on storylines and character traits that they've basically taken over(except for the satirical "The Word" segment, which fills only three minutes of each show). When Colbert made a joke about marketing his sperm for artificial insemination -- "Stephen Colbert's Formula 401" -- it would have been a one-time throwaway joke on any other show. But it's become a long-running story, with Colbert hawking his "premium man-seed" at every opportunity, even cutting away from guest Garrison Keillor for a singing commercial for the product("I can't believe I was interrupted by a semen commercial," said Keillor). Another segment, "Cheating Death With Dr. Stephen T. Colbert," has turned into a story about the dangerous drugs being pushed by Colbert's fictitious sponsor "Prescott Pharmaceuticals." Colbert's 2006 Emmy loss to Barry Manilow inspired a running gag in which the host shakes his fist in the air and screams the crooner's name; Manilow recently appeared as a disembodied head and consoled Colbert on losing the 2007 award to Tony Bennett. As with a character on The Office or 30 Rock, you can construct a biography for Colbert's character based on the information given on the show.

The head writers of the show, Silverman and Rich Dahm, have said they always intended to do a show with story elements. Dahm, a former writer for Sacha Baron Cohen's Ali G character, told Variety that in writing the show, "one of our biggest tasks has been to develop a voice and a history for him." No matter what they personally think of current events, the important question for the writers is how would Colbert, the character, react to them. So when the U.S. had a day of immigrant protests, Dahm said, they decided that it would be in character for Colbert to not notice that anything was going on: "He had no idea why his housekeeper and driver and gardener weren't around."