From "Meet the Press"
Interesting not only for the endorsement, but that he also makes several criticisms that some wanted Obama & Biden to address in the debates.
Some might consider this an act of retribution for having been made the fall guy for the missing WMD's.
I believe, were that to happen, it would come in a much more direct manner - though, given what I've seen of Mr. Powell, we'd necessarily know of his direct connection.