Fair and Balanced?

It is being reported that Fox News is refusing to run an Anti-Alito television ad, claiming it is relying on its lawyer's assessment that the ad is "factually incorrect" in the way that it portrays a particular Alito decision. The story is in the Washington Post, and oddly enough, the same story appears on the Fox News site as well (I assume they just automatically download external news feeds).

Obviously Fox has the right to refuse to run or not run any ad it likes, but this seems awfully questionable to me. Does anyone know whether Fox has ever refused to run a political ad previously on the basis that its claims were "factually incorrect"? The reliance on the "lawyer's advice" seems a bit forced here too--surely Fox doesn't think this crosses the line to slander, does it? I haven't found any more detailed explanation from Fox (such as a press release or something), so if anyone else has found anything like that, please pass it along. At first glance it is hard to rebut the hypothesis that this decision is about politics rather than the accuracy of the ad.

This also reminds me of one of the more unusual experiences I had while at the FTC--a petition was filed by moveon.org and Common Cause for the FTC to bring an action against Fox on the basis that its slogan "Fair and Balanced" was misleading to consumers, because Fox wasn't really "Fair and Balanced." As you might assume, the complaint was dismissed.

Update:

A Comment answers my question by pointing me to this version of the story, which appears to be a longer version of the Washington Post story I linked and contains a tidbit that the Washington Post version of the story omitted. The longer article notes that Fox previously refused to run one ad by the Swift Boat Veterans for Truth and another ad from the RNC for other reasons:
"It's not about ideology, it's about quality and honesty," Irena Briganti, a Fox News spokeswoman, said of the decision to reject the ad.

She noted that Fox had refused to run one ad by Swift Boat Veterans for Truth in which Democratic presidential nominee John Kerry was called a traitor and recently turned down a spot from the Republican National Committee because of content and its use of excerpts from other news programs.

Update:

Daniel Chapman provides the FactCheck.org analysis of the ad.