Grand inquisitor: White House diva Helen Thomas has grilled every president since JFK. (The Object At Hand).

The Washington, D.C. cabdriver couldn't quite place her but knew that the passenger, a diminutive woman with short dark hair, was somebody important. Finally, the cabbie turned around and asked straight out: "Aren't you the woman the presidents love to hate?"

Helen Thomas, who at age 82 is the indisputable dean of the White House press corps, tells that story on herself. For decades, she has posed the opening question at every presidential press conference, then closed the event by saying, "Thank you, Mr. President." As a correspondent and White House bureau chief for United Press International for most of her 60-year career, Thomas has been a journalistic thorn in the side of every president from John F. Kennedy to George W. Bush. "She has single-handedly gotten under the skin of every president since JFK," says Mike McCurry, press secretary during the Clinton years. As Gerald Ford once observed, Thomas practices a "finely balanced blend of journalism and acupuncture." Jacqueline Kennedy was less subtle: she referred to Thomas and her Associated Press counterpart as "the harpies."

But history has a way of arranging ironic rebuttals. For just as Jackie's off-white silk chiffon inaugural gown now resides in the Smithsonian's National Museum of American History, so too do three of Thomas' White House press passes, showcased in the "American Presidency" exhibit. "The press curbs presidential power," says curator Harry Rubenstein. "And Helen Thomas epitomizes the White House press corps."

Says Bob Deans, one of Thomas' colleagues and the White House correspondent for Cox Newspapers: "She has great respect for the office of the presidency. But she is not intimidated by the person who temporarily inhabits the office." Thomas' conduct of this epic adversarial relationship is unstinting, although she no longer works out of the UPI cubicle in the White House. She resigned from that organization in 2000, after the wire service changed ownership.Today, Thomas, who still occupies her traditional front-row seat in the briefing room, covers the White House in a column for the Hearst newspapers. Formal seat assignments notwithstanding, most spots are up for grabs. "But no one sits in Helen's seat," says Martha Joynt Kumar, professor ...