The choice of Colbert quickly drew the ire of a real-life conservative talk- show host. Radio's Rush Limbaugh said Thursday that CBS "has just declared war on the heartland of America. No longer is comedy going to be a covert assault on traditional American values, conservatives. Now it's just wide open."
Limbaugh mispronounced Colbert's name as col-bert, instead of the proper pronunciation, col-bear.
The man Colbert is replacing was a target for conservatives, too. Letterman made Republican favorite Sarah Palin a frequent target of his barbs.
Tassler declined comment on what Colbert's ascension will mean for Craig Ferguson, who follows Letterman's show in the 12:35 a.m. time slot and was considered a candidate for Letterman's job.
Colbert would likely enter into some friendly competition with Fallon. Colbert appeared on Fallon's first "Tonight" show, one of a line of personalities in a gag involving people who had to "pay up" on a bet about whether Fallon would ever get the "Tonight" gig.
Brad Adgate, an analyst for Horizon Media, described Colbert as "the best talk-show host available." He said CBS wanted to move quickly to make its choice for Letterman's replacement before next month's meeting with advertisers in New York about the upcoming season's schedule.
"When you've got fire in the belly, you move fast," Tassler said.
Associated Press Writers Frazier Moore, Jake Coyle and Mesfin Fekadu in New York, and Lynn Elber in Los Angeles, contributed to this report.
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