The man who promised to "restore dignity to the White House" has had a pratfall. George W. Bush is, to use his father's immortal phrase, "in deep doo-doo."

Having vowed he never would, the Republican presidential candidate is answering questions about previous drug use. He has made himself, despite his astronomical poll ratings and his groaning treasury, a mere mortal.

Bush's angry progress last week--from Louisiana, where he said emphatically on Wednesday that he could meet the FBI application standard about no drug use in the past seven years, to Virginia, where he said the next day that he was clean during his father's presidency--was the landscape-altering event his opponents have prayed for. His staff has put the cutoff date for doing what he has not yet admitted doing at age 28. The awkward question of whether he could qualify for a White House staff appointment, the application for which asks about drug use back to age 18, is still hanging in the air.

Can he survive? He can. He is still personable and engaging. He still has his record as a madly popular Texas governor. He still has his name, which stirs Republican pride--and guilt that his father lost to Bill Clinton. He has the cover of claiming to be born again on his 40th birthday. He has discussed his wild youth. Did it end at 40? Republicans have a more extended view of when middle age begins. Chairman Henry Hyde of the House Judiciary Committee, which sat in judgment on Clinton, called his own affair with a married woman at the age of 46 "a youthful indiscretion."

In striking back, Bush has lashed out at the press, at "the politics of personal destruction." He has sought to be praised for his refusal to play "the Washington game" of making a candidate prove a negative. He played the same game himself quite enthusiastically when he told the world that he had been a faithful husband. It was plainly an attempt to cast himself as a person morally superior to the current occupant of the White House.

For Bush, the worst aspect of the whole thing may be that he has now invited comparison with Clinton, the man he is trying to run against. Bush strategists know that the man who will likely be the Democratic nominee, Al Gore, suffers greatly from Clinton drag, the so-called "Clinton fatigue" that keeps the vice president sinking in the polls.

Bush isn't handling drug queries any better than Clinton did in 1992. When the governor of Arkansas was asked, as were all politicos who grew up in the tumultuous '60s, if he had been part of the drug culture, he tap danced for months. He started out with "none of your business"--but the press continued to press. Clinton said defiantly that he "had never broken the laws of my country."

Finally, during the New York primary, a reporter framed it more sharply: Had Clinton used drugs as a Rhodes scholar at Oxford? He admitted that he had "experimented with marijuana." His embellishment, that he "didn't inhale," has passed into the political lexicon as a synonym for weaselly irrelevance. The questioning ended there.

Bush, however, must expect more. Bush's blanket alibi of behaving irresponsibly when he "was young and irresponsible" will not suffice. It won't satisfy people serving stiff cocaine sentences in Texas jails.

It could well be that Bush had his own family rather the country in mind when he was stubbornly refusing to answer questions about drugs. Drug counselors urge users to keep their past a secret from their children. Bush is the father of teen-age twin girls.

Whatever his reasons, he now has a new and daunting mission to perform. He must demonstrate that he is a serious person, a premise seriously questioned in a story by Tucker Carlson in Talk magazine. Carlson is a pleasant young conservative with a sharp pen. He depicted the governor as a swaggerer deficient in the compassion he claims. Bush laughed at a woman whose death sentence he declined to commute, Carlson wrote.

Bush was miffed by what he regarded as friendly fire. His excuses were lame: It wasn't a serious interview, they hadn't been seated at the time.

Bush was First Son at the White House; he must have watched his father stand up at a microphone and speak of momentous things. He should know that many presidents fling headlines over their shoulders while hurrying to their helicopters.

Now he has to prove he is a thoughtful man who considers carefully what he says. He has to convince the country he learned something important from his wild youth. It doesn't matter what he did 25 years ago. But what he says about it does matter. He must, in short, demonstrate maturity. We've had a teen president for the last seven years. It may not be quite time for another.