Mr Bush says the controversy is politically motivated
The Bush administration is on the defensive after it was revealed that it was warned of plans to hijack US airliners more than a month before the attacks of 11 September.
Democrats and some members of Mr Bush's own party are calling for the administration to reveal what was known and when.
In closed-door meetings, Mr Bush told fellow Republicans that he believed this was a partisan attack, saying, "There is a sniff of politics in the air."
Terrorism experts fear that the politicisation of the issue might derail much needed reforms of US intelligence agencies.
And one intelligence expert said the Bush administration should be more open and co-operate fully with the congressional inquiries, or it risks losing public support.
Although Mr Bush believes the controversy is politically motivated, he cannot ignore the outrage expressed by families of the victims.
Donn Marshall's wife Shelley died at the Pentagon. "It sort of makes you wonder where the get-tough president was when he was getting all this information, why they didn't react act more vigorously," Mr Marshall said.
Stephen Push's wife of 21 years, Lisa Raines, died when the plane she was on hit the Pentagon.
"It's shameful that they know as much as they did and didn't warn anyone. They put the business interests of the airlines above the lives of the citizens," Mr Push said.
Bush defence
The Bush administration stepped up damage control efforts on Thursday with a rare public briefing by National Security Adviser Condoleezza Rice.
However, she defended the president, saying that the threats were general and that most focused on targets outside the US.
"If this president had known something more specific - that a plane would have been used as a missile - he would have acted on it," Ms Rice insisted.
Counter-terrorism expert Thomas Badey says that the Bush administration would have been hard pressed to piece together the disparate bits of information they had in order to prevent the attacks of 11 September.
"Ninety percent of intelligence failures are not failures to collect information but failures to put it together properly," Mr Badey said.
The failure of US intelligence to predict and prevent the attacks of 11 September was simply a failure to make sense of the bits of information collected by various, and often isolated, US agencies.
Despite the knowledge of previous plans to fly aircraft into landmarks such as a 1995 Algerian plot to fly a jet into the Eiffel Tower, "is it reasonable with the information known at the time to expect that President Bush knew something like this would happen? No," he said, adding, "Politics are at play."
Mr Badey is not surprised that the controversy began immediately after the Republican National Committee launched a fund-raising campaign showing President Bush as a central figure in the fight against terrorism.
But he sees this as part of a larger trend that has politicised the fight against terrorism.
From political fund-raising to the storage of nuclear waste in Nevada, terrorism is being used to support one cause or idea over another, he said.
And he fears that such politicisation might interfere with reforms designed to streamline US intelligence efforts.
Secrecy
Loch Johnson has served in two investigations of the CIA: The Church Committee investigation in 1975 and Les Aspin's review of the agency after the end of the Cold War in 1995.
Both investigations fought an uphill battle to wrest information from the CIA and other intelligence agencies.
"It's part of a cult of secrecy in the executive branch. They think they are the high priests of access of information. They think that legislators and their staff cannot be trusted," he said.
And he claimed: "The Bush administration is more secretive than any administration since Nixon's."
He said that such a strategy might backfire. He predicted that public opinion might turn against President Bush "if the public finds out there is insufficient co-operation from the administration".