As Jonathan Martin points out, there's a pattern emerging of top Giuliani supporters leaving the campaign, whether for better gigs or because of scandal. Today, we learn that Sen. David Vitter (La.) is one of the names on the so-called D.C. Madam's client list.

Vitter was the first senator to endorse Giuliani and serves as his Southern Regional campaign chair. Back in March, National Journal's Hotline expressed the sentiment of many: "Let's give Giuliani his due: having Vitter will help whip support among Southern conservatives, and qualifies, to us at least, as a major and important endorsement."

Indeed, a nod from Vitter gave Rudy a bit of cover from southern conservatives worried about voting for a social liberal from New York. However this plays out for Vitter, who is not up for reelection, it puts Giuliani in a difficult spot.