So Bush can be blamed for allowing the attack to happen, but not praised for preventing another one.
Man I have got to take a course in Liberal Logic one of these days.
Well, we have to spend a few years thinking happy thoughts and pretending that the people who planned 9/11 weren't planning it.
There are several steps to this.
1. Ignore that the planners were never arrested.
2. That it took years, most of which Bush wasn't President, to plan and coordinate that attack.
3. That the planners were free to plan because we arrested "all the bad guys" and put them in prison here in the US. It is "successful" policy to put them in jail, nothing bad can come from that.
4. Pretend that returning to that failed policy will net us a different result.
If you suspect that you are beginning to falter rinse and repeat.
If you do that, it becomes easy to blame Bush. It also helps if you think that failed policy is something new and "change". Moving from a new failed policy, to return to a previously failed policy will therefore be "change" and new, bright and shiny.