How much corporate experience is needed for the Secdef job? I am not asking in terms of a Jack Welsh type here. Rather, given the nature of overseeing weapon systems development and procurement on a massive scale, I imagine some private sector experience would be necessary. What is a good rule of thumb?

Could Michael Vickers end up Secdef someday? Is his background too unconventional? He does not seem to be lacking in the brains department, this much is certain.