WASHINGTON, 27 March 2004 — For one of the first times in the presidency of George W. Bush, his White House has been forced onto the defensive. And the general atop the battlements is his National Security Adviser Condoleezza Rice.

The Bush mantra has always been that the best defense is offense, so Rice has been hitting back hard — using television appearances and media briefings to try to undermine the credibility of Richard Clarke, the former counterterrorism chief who contends that Rice and the rest of the administration failed to respond to repeated warnings about terrorist threats. But Rice’s aggressive strategy risks damaging her own credibility, rather than Clarke’s.

“Rather than deal with the substance of what he’s saying, they’re trying to impugn his character,’’ said Nancy Soderberg, a deputy national security adviser during the Clinton administration. “It’s not a campaign issue, it’s an issue of national security, so I think their pit-bull tactics are going to backfire.’’

Although Rice has made herself available to news outlets, she has refused to testify before the independent commission investigating the Sept. 11 attacks. That panel questioned a series of current and former government officials this week, including Clarke. As a result, the controversy created by Clarke is increasingly focusing on Rice, perhaps the president’s closest adviser.

Mary Fetchet, co-chair of Voices of September 11th, an advocacy group for families of the victims of the 2001 attacks, argued that Rice was key to the flow of information and therefore should testify about what she knew. “I wish she would just skip the television interviews and take the time to testify in an open hearing under oath,’’ said Fetchet, whose son, Bradley, died in the World Trade Center. “I believe that I deserve the answers to the questions I have, and so does our country.’’ Rice spent four hours last month behind closed doors with members of the commission, and on Thursday requested a second private meeting, but such appearances do not carry the same weight, in the eyes of the public, as testimony under oath. She contends that the principle of executive privilege means that her advice to the president should remain private.

Many former officials from both parties agree, saying presidential advisers need reassurance that they can offer their opinions without fear of public questioning.

“She can meet informally with them; she can do a lot of things to accommodate them’’ short of testifying, Soderberg said.

But as the days pass and the controversy intensifies, that argument may be losing ground. Stephen Hess, a presidential scholar at the Brookings Institution who served in both the Eisenhower and Nixon White Houses, said the Bush administration will have a hard time deflecting damage from Clarke’s allegations unless Rice agrees to testify. “There are principles involved, and fair enough. But there are some questions being raised about her probity,’’ Hess said. “When a person’s own honesty or probity is in question, I think they should be given the right to testify.’’

For their part, Democrats in Congress appear unwilling to let the issue go. In addition, Rice’s repeated media appearances this week seemed to add insult to injury, at least in some quarters.

“We need Condoleezza Rice, who seems to have time to appear on every television show, to make time to appear publicly before the 9/11 commission,’’ Senate Minority Leader Tom Daschle, D-S.D., said Thursday. “She is not constrained by precedent from doing that, as the White House has argued. ... I’ve reluctantly reached the conclusion that what really constrains Ms. Rice’s full cooperation is political considerations.’’

The chief political consideration, of course, is Bush’s re-election campaign, which is already in full swing. And the White House testiness about Clarke reflects the importance of terrorism — and Bush’s portrayal of himself a “wartime president’’ — to his reelection bid.

But Rice’s reactions are also personal, as has become clear from her comments to the media. David Gergen, who has advised embattled presidents of both parties, noted that the code of conduct in Washington used to be that White House tell-all books did not come out until a president’s first term was over. “(Rice) feels it’s a stab in the back, but it’s also a knife in the heart of what the Bush presidency is all about,’’ Gergen said. “They really do need to rebut it.’’

All the same, he said, Rice’s TV appearances don’t appear to have done the job, in part because her sense of personal affront has made her seem shrill or strident at times. Gergen described the White House response as “carpet-bombing’’ and said the overall impression was one of overkill.

“They are blunting some of Clarke’s effectiveness, but at a considerable price,’’ Gergen said. “There is a spreading sense that they really try to smash anybody who disagrees with them.’’

Moreover, as the controversy has become more partisan with each passing day, Rice may have damaged her public image as the national security adviser — a position traditionally seen as above the political fray.

To understand the White House response, both insiders and observers alike say it’s important to recognize that the most cherished value in the Bush administration is loyalty. As a result, Rice and others are reacting to Clarke’s disloyalty, not to the substance of his criticism.

“If Dick attacked me that way, I too would be angry,’’ said Clinton’s National Security Adviser Anthony Lake. “But I know him, and he is an equal opportunity junkyard dog who is driven by wanting to get things done.’’