And WJC is a man who's word can be taken as a solemn vow, right?
Clark was a trial ballon, nothing more. If he rises to the occassion and takes off in popularity a Clark-Clinton ticket was/is a possibility. But the Clinton's would accept that only if they know Clark will lose.
If Clark fails as a potential candidate this year, then the Clinton's will cross him off of their list of potential VP candidates for 2008.
Clark is looking more and more like an boob, who has no real potential to be President. He would bring nothing to the party in '08, from the Clinton's POV.