Now that the White House has acceded to mounting pressure and let Condoleezza Rice testify under oath and in public, she can help the 10-member investigating commission and the American people get to the bottom of what went wrong on Sept. 11, 2001.

The nation suffered a devastating failure in its primary responsibility of protecting the American people against attack. Finding out how and why that happened is essential, not primarily to place blame but more importantly to better prepare against future threats. Still, since President Bush has made his management of what he labeled as the war against terrorism the main thrust of his campaign for re-election, it is not enough to use the easy passive voice and say that “mistakes were made.” The commission must also ask who made the mistakes. It must have a thorough exploration of what both the Clinton and the Bush administrations did about the threat of terrorist attack by a radical Islamic conspiracy and what the Bush administration has done in response to the actual Sept. 11 horror.

The time for accusing Richard Clarke of trying to promote sales of his book and angling for a job in a Kerry administration is past. What is needed is a serious response to his serious charges that Mr. Bush was preoccupied with an Iraqi threat that turned out to be exaggerated and diverted troops and resources and attention from the real threat, Osama bin Laden’s al-Qaida terror network.

Dr. Rice was at the very center of the response of the Bush administration to the terrorism threat, from the day President Bush took office to the attacks eight months later. She can be asked to account for the long delay in formulating a plan for dealing with al-Qaida and its host in Afghanistan, the Taliban. She can be asked, too, about the “gaps and inconsistencies” reported on March 22 by The Wall Street Journal in a study of the various government accounts of what happened on Sept. 11. Among other tings, the Journal reported that it was not President Bush, as he claimed, but Air Force Gen. Richard Myers who ordered the military put on high alert.

The way now is open for Dr. Rice, as a key figure in the Bush administration, to help explain how it came about that 19 Islamic extremists could sneak into the country, hijack commercial jetliners and smash them into the World Trade Center and the Pentagon. She can also help us all understand how the Iraq war fits into the nation’s response to the terrorist threat.