sources: Wrestling Observer Newsletter
Raw head writer Brian Gewirtz was credited, or blamed, depending on your point of view, for booking Shawn Michaels to pin World Heavyweight champion Edge on his last night on Raw. Gewirtz's explanation was that guy leaving the territory, or brand in this case, has to job on the way out.
Triple H was the power behind the move because when it was questioned, he supported it, which made it close to a done deal. There is a belief backstage that Triple H doesn't want Edge to succeed, noting that he tried to block all previous plans of him to moving to SmackDown and winning the title until Mr. Kennedy went down with an injury, and at this point he couldn't reasonably block it anymore. There was vocal opposition to Edge being pinned, saying that it makes the SmackDown title and champion look secondary. Triple H's argument was that HBK is the biggest tenured star on the brand, and he had just put over Khali, and he needs a big win because he'll be wrestling Cena on PPV again within the next few shows. On the other hand, Michaels suggested doing a non-finish, since from his perspective, the key point of the match was for him to be beat down by Randy Orton to promote their match for tonight at Judgment Day. Michaels said he didn't want to bury the SmackDown title but was told it was Vince McMahon's decision and he wasn't changing it.
As you might imagine, Edge wasn't pleased with the booking decision and he wasn't hiding his dissatisfaction backstage that night. Edge is said to be happy to move over to Smackdown because internally it's considered less political, not to mention that he doesn't have to deal with a certain wrestler as much anymore.