Can Clark be SecDef? (POLL)

I know lots of folks here want Clark for VP.  My only reason for being uneasy about that is that Clark isn't the kind of natural electoral politician Edwards is.  Clark's talents relate more to having good foreign policy ideas than winning elections.  (I loved his recent Washington Monthly piece, but I thought he seemed a little confused about what to do on the campaign trail.)  What I'd really like is for Kerry to announce an intention to make him Secretary of Defense.  State also is a possibility -- and perhaps one more suited to Clark's talents -- but Clark as guaranteed SecDef would be a wonderful contrast with the embattled Rumsfeld.  Is this possible, though?  I heard that there are some restrictions on how soon a general can move to the SecDef position.  Your thoughts are appreciated.

(said WaMo piece is here)

http://www.washingtonmonthly.com/features/2004/0405.clark.html