Federal campaign law requires broadcasters to give all candidates equal time on the airwaves. That rule applies to entertainment programs like "Law & Order," meaning stations that run the show would be required to give other GOP candidates a like amount of prime-time exposure. As a practical matter, the television stations would in all likelihood have to pull all of the Fred Thompson shows for the duration of his candidacy.
Candidates' appearances on newscasts, interview programs and at news events are exempted from the rule. So are incidental appearances in documentaries.
But the rule has been applied to television and movie stars in the past.
During the 2003 gubernatorial race in California, television stations dropped all Arnold Schwarzenegger movies out of fear that showing them would require them to give countless hours of free airtime to all 134 other candidates for governor.