Washington ? Congressional Democrats demanded Thursday to be told what President Bush knew about terrorist threats before Sept. 11 as the White House and its GOP allies defended the president for not disclosing intelligence last August that Osama bin Laden wanted to hijack U.S. airplanes.

“You would have risked shutting down the American civil aviation system with such generalized information,” said National Security Adviser Condoleezza Rice. “You would have to think five, six, seven times about that, very, very hard.”

With politically charged hearings looming, the White House scrambled to shield Bush from damage, and Democrats sought to exploit a potential crack in the president’s record-setting popularity. Worried aides dispatched top advisers, including Rice and Vice President Dick Cheney, to public venues as the controversy mushroomed.

“What we have to do now is find out what the president _ what the White House knew about the events leading up to the events of 9-11, when they knew it and, most importantly, what was done about it,” said House Minority Leader Dick Gephardt, D-Mo.

Cheney called Democratic criticism “deeply disturbing” and warned foes to tread lightly. “They need to be very cautious and not seek political advantage by making incendiary comments,” he said in a speech to New York conservatives.

Rice said the intelligence, tucked in a 1-page CIA terrorism report given to Bush during an Aug. 6 briefing while on vacation in Texas, mentioned bin Laden’s al-Qaida network and “hijacking in a traditional sense” _ not suicide hijackers slamming fuel-laden planes into American landmarks. She said the administration learned of increased threats of terrorism in May, earlier than previously disclosed.

The public was not informed of the threats, which Rice said were vague and uncorroborated.

“The most important and most likely thing was that they would take over an airliner, holding passengers and demand the release of one of their operatives,” Rice said of the report’s reference to al-Qaida. She said the terrorists wanted to hijack a plane and demand the freedom of the “blind sheik” Omar Abdel-Rahmen, the Egyptian cleric imprisoned for a plot to bomb targets in New York in the early 1990s.

The report discussed a variety of methods terrorists might deploy against the United States, including biological and chemical weapons, sources said.

Democrats and some Republicans pressed Bush to hand over the top-secret CIA analysis and release an FBI memo written even earlier that warned headquarters that many Middle Eastern men were training at U.S. flight schools.

White House officials were divided over whether to release them.

Republican Sen. Richard Shelby of Alabama, vice chairman of the Intelligence Committee, said, “There was a lot of information. I believe and others believe, if it had been acted on properly we may have had a different situation on Sept. 11.”

Bush had no public comment on the developments, but suggested in a closed-door meeting with GOP senators that politics might be at play.

“He said if there had been a strong warning to trust him that he would have reacted quite forcefully,” said Sen. Lincoln Chafee, R-R.I., who attended the Capitol luncheon.

“He reminded us this is the political season,” Chafee said.

By day’s end, White House officials and GOP allies were hewing the same line: Democratic attacks could backfire.

“There’s really nothing more despicable … in American politics than for someone to insinuate that the president of the United States knew that an attack on our country was imminent and did nothing to stop it,” said Senate Minority Leader Trent Lott.

Rice described a series of threats uncovered by intelligence officials, beginning in September of 2000 and reaching heights in May and the summer of 2001, that dealt mostly with American interests overseas.

Those threats prompted a series of alerts from the FBI to law-enforcement agencies and from the Federal Aviation Administration to the nation’s airlines and airports _ well before Bush was briefed about the threats, she said. However, officials with the airline said they did not receive any specific information about potential hijackings.

White House officials said the government did not ask airlines to tighten security because threats of traditional hijackings have been almost standard fare for years.

“Even in hindsight, there was nothing in what was briefed to the president that would suggest that you would go out and say to the American people, ‘Look, I just read that terrorists might hijack an aircraft,'” Rice said.

However, there were reasons to suspect suicide attacks with airplanes. In 1994, for example, Algerian terrorists hijacked a plane in a foiled attempt to destroy the Eiffel Tower. And in 1995, terrorists in the Philippines plotted to hijack several U.S. planes, and there was even talk of crashing into CIA headquarters.

Rice said the Eiffel Tower and Philippines incidents were not part of Bush’s briefing, and neither she or Bush could recall seeing the FBI memo.

“Had this president known of something more specific or known that a plane was going to be used as a missile, he would have acted on it,” she said.

Transportation Secretary Norman Mineta said there was “no specificity to the information” that his agency passed on to airlines and airports last summer.

“There was no way we could have, let’s say, connected the dots to point to what happened on the 11th of September,” Mineta said.

Sorting through the tumble of events, some family members of the Sept. 11 victims reacted with anger.

“I believe our whole government let people down,” said Bill Doyle of New York City, whose son, Joseph was killed inside the World Trade Center.

Other loved ones said the government probably did all it could.

“It’s time to put aside the anger, the frustration,” said Peggy Neff of Hyattsville, Md., who lost her partner of 17 years, Sheila Hein, in the Pentagon attack.

Democrats expressed skepticism about the administration’s explanations.

“Why did it take eight months for us to receive this information?” asked Senate Majority Leader Tom Daschle, D-S.D.

With intelligence panels already trying to determine whether the government ignored warning signs, Daschle said this week’s development will throw the investigation to other panels.

Sen. Hillary Clinton, D-N.Y., said she would never second-guess a commander in chief _ then she called on Bush to explain why he didn’t make the threats public in August.

Some Republicans demanded answers, too.

“There were two separate FBI reports plus a CIA warning, none of which were coordinated,” said Sen. John McCain, R-Ariz. “The question is, If all three had been connected, would that have led to more vigorous activity? That’s the reason why we need the commission to look at it.”

Gephardt and several members of intelligence panels, primarily Democrats, said they had not been advised of the threats although the White House insisted that committee members were told.

White House officials said Bush was unwavering in his belief that CIA Director George Tenet and FBI Director Robert Mueller had done a good job overhauling their agencies to close the gaps exposed by the attacks. Their jobs are not in jeopardy, officials said.