CNN, which ordinarily draws big ratings for live coverage of special events, saw its audience plunge Tuesday night for its coverage of the Iowa caucuses. According to Nielsen Research, total viewers dropped to 1.3 million -- 41 percent below the 2.2 million viewers who tuned in a year ago. As it did last year, Fox led the ratings race with 2.6 million viewers, up slightly from the 2.46 million it attracted in 2008. The results reflected the fact this this year interest in the caucuses was focused on Republican candidates, while in 2008 both parties were engaged in tumultuous Battles. Republicans represent a majority of Fox News's audience.