Presidents and their staffs resemble the families described by Tolstoy: All happy ones are alike while each unhappy one is unhappy in its own way. Scandals have a particular capacity for focusing this unhappiness. Richard Nixon's White House during the Watergate scandal was invested with the conspiratorial attitude that was an attribute of this distrustful president. Ronald Reagan's White House, more trusting, was bewildered by the Iran-contra scandal. Bill Clinton's aides were embarrassed by their president's insistence that his affair with Monica Lewinsky had nothing to do with the conduct of his presidency, but nearly all of them adopted this argument as their own.

George W. Bush and his team, reeling from the miscalculations and hubris that so often attend second-term presidencies, have reason to be unhappy. Neither the Iraq war nor the president's domestic agenda command widespread support. Bush's approval rating is lower than Reagan's or Clinton's at the depth of their scandals. Roughly two-thirds of Americans say the nation is on the wrong track.

Administration defenders searching for a silver lining in the White House gloom have observed that Bush -- unlike Nixon, Reagan or Clinton -- is not a suspect in the scandal that resulted in the indictment of his vice president's chief of staff. Assuming this is true, it's not entirely an advantage. Yes, Nixon's central role in the Watergate coverup forced him from office, but only because he persistently lied about it. Reagan created the Iran-contra scandal, in which several of his national security aides participated, by authorizing secret arms sales to Iran in defiance of his public policy and the counsel of his secretaries of state and defense. Clinton's involvement with Lewinsky was the scandal.

But the very centrality of Reagan and Clinton to their predicaments enabled them to do what Bush cannot: acknowledge responsibility and seek forgiveness. In Reagan's case, it took some prodding, much of it from his wife. Nancy Reagan brought into the White House a diverse array of people, including Democratic power Robert Strauss, whose message was to level with the American people. Reagan did. "A few months ago I told the American people I did not trade arms for hostages," Reagan said in a nationally televised address on March 4, 1987. "My heart and my best intentions still tell me that's true, but the facts and the evidence tell me it is not."

That wasn't all. Again under prodding from his wife, he replaced Donald Regan, his besieged chief of staff, with former Republican Senate leader Howard Baker and named Frank Carlucci to replace a disgraced national security adviser as part of a general housecleaning. Baker and his successor, Kenneth Duberstein, ran the White House smoothly for the rest of the presidency.

Mindful that President Bush has tried to model his presidency after Reagan's, some Republicans have urged him to broaden a circle of advisers that has not notably widened in his second term. Relying exclusively on a small cadre of loyalists can be a problem in any line of work, but it is particularly a recipe for disaster in the White House. During the years I covered the presidency for this newspaper, I knew many capable White House aides who found their jobs exhilarating but who burned out under the heavy workload and unrelenting pressure. The strain of working in the hothouse environment of the White House is especially acute during a scandal. Bringing in new people in such circumstances can be an act of kindness as well as a political necessity.

Whether Bush can easily dispense with his embattled political adviser, Karl Rove, and other loyalists isn't clear. Bush is more devoted to the advisers who have been with him since Texas than Reagan was to his core group of Californians, and more dependent on them, too. Reagan had been used to new directors and cast members since his Hollywood acting days, and he did not regard anyone except his wife as indispensable. Martin Anderson, an observant economic adviser, once described his boss as "warmly ruthless." Although Reagan had stubbornly defended Don Regan, he didn't miss him when he was gone. Soon he acted as if Howard Baker had been his chief of staff all along.

Changing the guard cannot by itself solve Bush's problems. The nation was not at war when scandals struck the Reagan and Clinton administrations, and the policies of these presidents were, on the whole, more popular than Bush's policies. Bush is in large measure hostage to the war he began. But Reagan's success in the last years of his presidency, when he pursued a fundamental change in U.S.-Soviet relations, would not have been possible with the tired and discredited team he replaced because of the Iran-contra scandal. Reagan's example could be a useful guidepost for George W. Bush.

Lou Cannon covered the White House for The Post during the Nixon, Ford and Reagan presidencies and is the author of "Ronald Reagan: A Life in Politics." His e-mail address is