If John Kerry is elected president, I predict he will ask General Colin Powell to stay on as Secretary of State! Whether or not General Powell would accept...well I don't know.
If Clarke is made Secretary of State, the first thing he'll do is give airline discounts to Islamic foreign nationals, then write a new book blaming Kerry for the subsequent rash of terror attacks.
Are you referring to Richard Clarke? I doubt that very seriously. He'd be more likely to head up defense, but I doubt Kerry will give him a job other than perhaps counterterrorism advisor.
If you are referring to Genl. Wesley Clark, yeah he could be Secretary of State, but I like him better for defense also.