Mr. Sanford stammered when asked to lay out the economic differences between Mr. McCain and President Bush.
Mr. Sanford's response was transcribed by CNN as: "Yes. I mean, for instance, take, you know -- take, for instance, the issue of -- I'm drawing a blank, and I hate it when I do that, particularly on television."
Eventually, he pointed to the North American Free Trade Agreement, but CNN Late Edition host Wolf Blitzer reminded Mr. Sanford that Mr. Bush and Mr. McCain shared support for the trade deal.
Bloggers and political pundits seized on the episode as proof that a key McCain ally could not put down the criticism that Mr. McCain's election would amount to a "third Bush term."