That seems odd

I had heard that if Fred Thompson was going to run for president he would have to leave Law and Order because of campaign laws. I thought it sounded familiar, like I had heard something similar about Arnold not being able to act during the campaign or while in office. I wasn't sure what the rationale was for the prohibition so I did a little looking around and found this article (WaPo - Fred Thompson's Presidential Hopes Could Put 'Law' Reruns in Lockup). It appears that it is tied to the equal air-time provision.

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.

Okay, that sorta makes sense, but what doesn't really make sense to me is that it doesn't apply to all air-time.

Candidates' appearances on newscasts, interview programs and at news events are exempted from the rule. So are incidental appearances in documentaries.

So why is it that the news media can talk about the front runners all day long and ignore the also-rans. It seems to me that that is much more inequitable than having the world see Fred Thompson play Arthur Branch for a few minutes on an episode of Law and Order. I just don't understand why news and talk shows are exempt from the rule. It seems unfair.