As it turns out, Bush was given a detailed briefing before Katrina:

WASHINGTON — In dramatic and sometimes agonizing terms, federal disaster officials warned President Bush and his homeland security chief before Hurricane Katrina struck that the storm could breach levees, put lives at risk in New Orleans’ Superdome and overwhelm rescuers, according to confidential video footage. Bush didn’t ask a single question during the final briefing before Katrina struck on Aug. 29, but he assured soon-to-be-battered state officials: “We are fully prepared.” The footage _ along with seven days of transcripts of briefings obtained by The Associated Press _ show in excruciating detail that while federal officials anticipated the tragedy that unfolded in New Orleans and elsewhere along the Gulf Coast, they were fatally slow to realize they had not mustered enough resources to deal with the unprecedented disaster. Linked by secure video, Bush’s confidence on Aug. 28 starkly contrasts with the dire warnings his disaster chief and a cacophony of federal, state and local officials provided during the four days before the storm.

Just to be clear, since the press seems to be missing it, this means that not only did PLENTY of people anticipate the levee’s failure (contrary to Bush’s claim), but some of those people BRIEFED HIM ON THAT VERY POSSIBILITY only days before he lied to everyone about it.