Washington - President George Bush agreed to do what he had insisted for weeks he would not: allow National Security Adviser Condoleezza Rice to testify publicly and under oath before an independent panel investigating the September 11 terrorist attacks.
The White House also agreed on Tuesday that Bush and Vice President Dick Cheney would answer questions - together, in private - before the entire commission.
The turnabout reflected administration concern that the president's strongest point with voters - his leadership in the war on terror - could be eroded if the high-publicity dispute over Rice's testimony lingered.
"I've ordered this level of cooperation because I consider it necessary to gaining a complete picture of the months and years that preceded the murder of our fellow citizens on September 11, 2001," Bush said.
"Our nation must never forget the loss or the lessons of September the 11th, and we must never assume that the danger has passed," he said in short remarks in the White House briefing room. He took no questions.
The commission's Republican chairman, former New Jersey Governor Thomas Kean, welcomed the decision and said the White House shouldn't be concerned that the testimony would violate the principles of executive privilege or separation of powers.
"We recognise the fact that this is an extraordinary event," Kean said. "This does not set a precedent." He said there was still no time set - either for Rice's public testimony or for Bush and Cheney's private appearance. Administration officials said her appearance probably would come at the end of next week.
Bush is staking much of his re-election bid on his performance as president after the 2001 attacks.
But former Bush counterterrorism adviser Richard Clarke - in a best-selling book and testimony before the September 11 commission last week -contended the president had been slow to act against al-Qaeda before the attacks and compromised the anti-terror battle afterwards by going to war in Iraq.
Opinion polls suggest support for Bush's handling of the war on terror has declined. Two surveys out this week show the president's approval ratings on that issue are now in the high 50 percent range after being in the mid-60s for months.
Although the erosion has not hurt Bush in one-on-one polling against Democratic rival John Kerry, the White House saw a brewing problem.
It waged a vigorous counterattack on Clarke's credibility. But the many hours Rice spent rebutting Clarke in the news media only raised anew the criticism of the White House refusal to let her testify publicly.
Even some Republicans began saying the administration's argument on separation of powers should be tossed aside.
Commissioner Slade Gorton, a former Republican senator from Washington state, said he was delighted at Bush's change of heart, but he added: "I think the White House would have been better off if it had made the agreements sooner."
Bush has reversed himself in the face of political realities on several previous occasions, especially on the subject of the September 11 commission.
Most recently, the administration, which had wanted to restrict any access to the president by the panel to just one hour, relaxed that limit. At the same time, the White House had continued to insist that Bush and Vice President Cheney would meet only privately and only with the commission chairman and vice chairman.
The new agreement set several conditions.
White House Counsel Alberto Gonzales, in a letter to the panel, stipulated that the commission must agree to seek no more public testimony from any White House official and that Rice's appearance would not be viewed as a precedent.
Rice appeared before the panel in February, in a private meeting of which no transcript was made.
As for Bush, he and Cheney will appear before all 10 commissioners in a single, joint session, with one commission staff member present to take notes, Gonzales wrote.
Bush said he agreed to the change "so the public record is full and accurate" and because "the circumstances of this case are unique."
The commission accepted the White House conditions.
Commissioner Bob Kerrey, a former Democratic senator from Nebraska, said the president and vice president will not be under oath. And Gorton confirmed there would be no time constraints on their appearance.
Commissioner Tim Roemer, a former Democratic congressman from Indiana, said Rice should address Clarke's charges - including that the Bush administration took too long to develop its anti-terrorism strategy.
A group of relatives of September 11 victims said they were pleased the commission would be able to question Rice in public, but lamented the commission would not do so with other White House officials.