NATIONAL JOURNAL: Insulating Bush (03/30/2006):

Karl Rove, President Bush's chief political adviser, cautioned other White House aides in the summer of 2003 that Bush's 2004 re-election prospects would be severely damaged if it was publicly disclosed that he had been personally warned that a key rationale for going to war had been challenged within the administration. Rove expressed his concerns shortly after an informal review of classified government records by then-Deputy National Security Adviser Stephen J. Hadley determined that Bush had been specifically advised that claims he later made in his 2003 State of the Union address -- that Iraq was procuring high-strength aluminum tubes to build a nuclear weapon -- might not be true, according to government records and interviews.

[snip]

"'Presidential knowledge was the ball game,' says a former senior government official outside the White House who was personally familiar with the damage-control effort. 'The mission was to insulate the president. It was about making it appear that he wasn't in the know. You could do that on Niger. You couldn't do that with the tubes.' A Republican political appointee involved in the process, who thought the Bush administration had a constitutional obligation to be more open with Congress, said: 'This was about getting past the election.'"

Update: An article in the recent American Prospect that connects some of the dots from Waas's important article.