During the past three months, the big broadcast networks have essentially stopped covering most of the GOP presidential candidates, a lack of national news attention that presumably affects the national poll ratings used to determine which candidates are included in televised debates.

On Thursday, the Fox Business Network announced that New Jersey Governor Chris Christie and former Arkansas Governor Mike Huckabee would be dropped from Tuesday's prime-time debate stage because of their low ratings in national polls. Those low ratings shouldn't be a surprise; from August 1 through October 31, Christie and Huckabee received just six minutes and three minutes of coverage respectively on the ABC, CBS and NBC evening newscasts, according to a new analysis by the Media Research Center. (See chart for details.)