THE AMERICAN PRESIDENT is only secondarily a person. Primarily, he is a symbol of what America thinks about itself, what it wants, and what it believes. In retrospect, we can see that for some time what America wanted was an end to responsibility. So the more recent two presidents were irresponsible men. In very different ways, both played Tom Sawyer, the bad boy who isn't really bad. As it happens, the one time in my life I was inside the White House was on September 8, 2001. That weekend, Laura Bush presented the first National Book Festival, based on a regional book festival she had run for six years in Texas. There was a formal dinner on Friday evening at the Library of Congress, a magnificent hall, at which we sat at a table next to that of the Bushes. Over the weekend, there were readings, discussions, exhibits, all on the subject of books. Sixty writers of all kinds, from children's book authors to historians, from mystery novelists to poets, gathered in Washington that weekend at Mrs. Bush's invitation to promote literacy and the joy of reading, all culminating in a Saturday breakfast at the White House. Through it all, Mrs. Bush was a charming, intelligent, passionately involved hostess. A former teacher and librarian, she had pushed the idea of this festival in Texas, and now she was sponsoring it in Washington, out of a conviction in the values of literacy. We attendees came to honor the idea of the book, but by the end of the weekend we had all learned to honor Mrs. Bush. Frequently, in the two days of the festival, President Bush was at his wife's side, but he never said one word in public. He grinned, he winked, he waved at friends, he showed how proud he was of the little lady, but he never revealed a personality of his own. Except, of course, Tom Sawyer. Three days after that White House breakfast, those inhuman creatures with their own death-soaked values called America's attention to themselves, as they'd been trying to do for years. This time, they succeeded, but they accomplished far more than they set out to do. In the first place, they finally brought an end to the Vietnam war. For thirty years, America has been wounded, defensive, insecure, a braggart, and a bully because it was no longer sure of itself. Vietnam had broken America's belief in its own decency, the belief that had made it so useful and so cordial in the world for so long. A German friend once told me that, when he was a child, the first word one thought of in connection with Americans was "candor." After Vietnam, that was no longer the first word anyone thought of. With one slap across the face on September 11, that changed. America became closer to what it had been in 1960, self-confident without arrogance. The nation of the Peace Corps, not Grenada. Which meant that the symbol at the top had to change. In the first day or two after September 11, George W. Bush could be seen floundering, breathing open-mouthed like a fish, waiting for somebody to tell him what to do. But, more rapidly than I expected, he realized what he had to do. He had to become a grownup. The new suit does not fit perfectly, but that's all right. President Bush is performing a demonstration of stern determination, and is certainly doing it well enough to pass. We asked him to change roles in mid-performance, and he did it. We could not ask for more. Donald E. Westlake's latest novel, "Put a Lid on It," has some Washington moments.