Bush's actions are meant to EMPOWER the U.N. The Iraq situation is a win/win for the U.N.
If the U.S. stands down, then the mighty U.N. is the new 'superpower'...able to restrain even the most rogue of the old superpowers.
If Bush launches war, the U.N. will someday do an Iraq job on the U.S. (can't have unsanctioned wars going on, so a new 'coalition' will be formed to fight the U.S...beginning with accelerated economic warfare from Europe).
This whole Iraq deal is about empowering the U.N.