What makes you think the U.N. will enter Iraq at the invitation of the U.S.? Bush was told not to go it alone and now he wants the U.N. to go in and clean up his mess.

Nobody wants to go in under American control so if the new, U.S. apptointed, Iraqi govt. can hold together for a week or so...the U.N. might go in after all. Unfortunately, this is very unlikely.