The political performance of George W. Bush since Sept. 11, 2001, capped last week by the White House´s role in dethroning Trent Lott and replacing him with Bill Frist, has left many marveling at the discipline and efficiency of the president and his advisers. Together they "have made the White House a power center in ways that I haven´t seen in a long, long time--all the way back to Lyndon Johnson," said Robert S. Strauss, the former Democratic Party chairman and perennial adviser to presidents.

Others are less impressed than alarmed by what they see as Mr. Bush´s flexing of executive muscle, overpowering the legislative and judicial branches. The new Department of Homeland Security, war preparations in Iraq, even stumping for GOP legislators last November- -each implies overweening ambition. "The Bushies want to bring back the imperial, imperious presidency," Maureen Dowd warned in her New York Times column this past autumn, citing White House overreach that included "Karl Rove´s gunning for the Democrats" in the midterm election.

Distrust of the "imperial presidency" is a venerable tradition that dates back to our nation´s beginnings. The founders, keeping the example of George III firmly in mind, took every precaution to ensure that the new republic would breed no homegrown tyrants. They envisioned a head of state who would "preside" rather than rule, functioning obediently within the system of "checks and balances" they had so carefully devised. At the first signs of executive strength, our early presidents, from John Adams on, were labeled despots-in-training, and the accusation continued long afterward. "Sic semper tyrannis" was John Wilkes Booth´s cry before he assassinated Abraham Lincoln. But the current notion of the "imperial presidency" is rooted not in the traditional fear of incipient monarchism but in its opposite, an almost cult-like fascination with executive power. Arthur Schlesinger Jr., whose book "The Imperial Presidency" (published in 1973) popularized the term, first made his reputation as a chronicler of two powerful presidents, Andrew Jackson and Franklin D. Roosevelt. He went on to serve in the administration of John F. Kennedy, whom he counseled to govern in the Roosevelt style.

Another Kennedy adviser, the historian Richard Neustadt, wrote memos to JFK drawn from his book "Presidential Power," which championed Roosevelt´s ad hoc, risk-taking style and denigrated the plodding, cautious approach of Kennedy´s predecessor, Dwight Eisenhower, a general who preferred to govern through established channels rather than simply imposing his will. A third Rooseveltian turned Kennedy adviser, James McGregor Burns, contended that a powerful White House was the keystone to democratic health. The presidency "has attracted neither power-mad politicians nor bland incompetents but the ablest political leaders in the land," Mr. Burns wrote in his book "Presidential Government." "As a general principle, the stronger we make the President, the more we strengthen democratic procedures and can hope to realize modern liberal democratic goals."

Throughout this period of high-flying presidential power, skeptical voices could be heard. Critics of the New Deal like Herbert Hoover feared that the federal bureaucracy was growing too big under FDR and might result in a war-based economy not easily dismantled in peacetime. Sen. Robert Taft, who led the Republican opposition in the 1940s and early ´50s, consistently tried to limit the growth of the presidency. His Ohio colleague Sen. John Bricker, presaging the anxieties of those who today oppose Mr. Bush´s "unilateralism," proposed a constitutional amendment that would have required congressional approval of any and all agreements with foreign nations. In 1959 the conservative theorist James Burnham argued that a centralized, "Caesarist" democracy had emerged in which Congress´s rightful role had been usurped by the presidency.

Not many took these dissenters seriously. They came, after all, from the losers´ camp. As long as presidents pursued those "modern liberal" goals, who could object? Only with the advent of leaders uncongenial to liberal commentators did the frightening image of the "imperial president" take hold. First there was Lyndon Johnson, who vowed to carry out the Kennedy agenda and did so effectively but unaesthetically. Gone was the attractive "vigor" and "vitality." In its place were LBJ´s "boundless power appetite and ruthless historical ambition," in the words of Theodore H. White.

More disturbing still was Richard Nixon, the principal villain in Mr. Schlesinger´s study of presidential overstretch. Observing Nixon´s presidency, patterned in so many respects on JFK´s, Mr. Schlesinger began to reconsider his hero´s conduct and concluded that JFK´s actions during the Cuban missile crisis--particularly his decision to inform rather than consult Congress--had set a bad precedent. "What should have been celebrated as an exception," wrote Mr. Schlesinger, "was instead enshrined as a rule."

Even so, Kennedy´s decisive lone-wolfing "beautifully fulfilled both the romantic ideal of the strong President and the prophecy of split- second presidential decision in the nuclear age." Alas, poor Nixon. He followed Kennedy´s script but added no romantic flourishes. His "imperial presidency" smacked of dictatorship; "the all-purpose invocation of ´national security,´ the insistence on executive secrecy, the withholding of information from Congress, the attempted intimidation of the press."

It is not surprising that historians should play favorites. What´s puzzling is that they have perpetuated the myth of the imperial presidency when it is so plainly at odds with the historical record. The truth is that every modern president has found power to be elusive, slippery and at times treacherous. FDR, fresh off his landslide re-election in 1936, tried to "pack" the Supreme Court, only to suffer a humiliating defeat at the hands of Congress. Four years later, he was elected to an unprecedented third term, yet he struggled uphill to persuade Congress and the people to intervene in World War II. And consider the fates of Johnson and Nixon. A strong challenge from Sen. Eugene McCarthy in the New Hampshire primary reduced the demiurge to a lame duck who could not lead his own party, let alone the nation. Nixon fared even worse. One year after the publication of Mr. Schlesinger´s book, the "imperial president" resigned, unable to govern amid the controversies of Watergate. In both cases a gifted leader riding the crest of a massive electoral endorsement was brought down by the same political process he was said to have overpowered. Yet the idea of the "imperial president" remains with us, trotted out whenever the man in the White House signs a fast- track trade agreement, affixes his name to a treaty, or signs an executive order.

Now it is Mr. Bush´s turn. He is accused of cynically invoking national security, of relying too heavily on a few trusted advisers, of defying world opinion even as he runs roughshod over Congress, the courts and the press. Never mind that he has repeatedly taken his case to the people, to legislators, to the U.N. Never mind that a shift of several thousand votes in key states last November would have prompted the pundits to dissect Mr. Bush´s weakness and revive the question of his "legitimacy." Never mind that had Trent Lott carried on his fight for another week we would now be reading detailed analyses of Mr. Bush´s hubris and of Karl Rove´s fatal miscalculations.

The "imperial presidency" is not a useful idea. It is an epithet, dredged up whenever a president combines strength with imagination. But even the strongest presidents have known, or learned soon, that they occupy an office fraught with risk and are never more vulnerable than when their power seems greatest. They are, in sum, leaders, not rulers--which means, of course, that they are not imperial at all. (OPINIONJOURNAL.COM 12/27/02)

Mr. Tanenhaus, a contributing editor at Vanity Fair, is writing a biography of William F. Buckley Jr.