Remember 2001? When we were searching for some outlet for our aggression against those who would commit atrocity on American soil? That was the fertile environment in which American hero Jack Bauer was born, when 24 premiered. However, as time's gone by and the Bush Administration has lost its flavor, so has Mr. Bauer's popularity.
This isn't just us talking, it's statistics. Oh, and the show's creators. "The fear and wish-fulfillment the show represented after 9/11 ended up boomeranging against us," says the show's head writer, Howard Gordon. "We were suddenly facing a blowback from current events." Specifically in the show's depiction of torture over the course of the last season, post the Abu Ghraib controversy, the ratings really dropped off in the second half of the season.
Now, we're not sure that it has anything to do with the political climate of the country, or if people are just tired of watching the same character mired in one unbelievable day-long situation after another, but the clincher is that apparently 24 had some trouble getting actors to do the show in the past year or so, as people reacted to the brutal depictions of torture therein.
Wall Street Journal.com: Reinventing '24'