SOME legal historians have been chipping away at one of the key anecdotes of 20th-century history: Franklin Roosevelt's showdown, in 1937, with the ''nine old men'' of the Supreme Court, and the famous ''switch in time that saved nine.'' The academic debate over what happened-or didn't happen-in 1937, says Laura Kalman, a history professor at the University of California at Santa Barbara, ''is really a debate about whether judges are moved by law or politics.'' It's a timely subject, given the upcoming confirmation hearings for Samuel A. Alito Jr., President Bush's nominee to replace Justice Sandra Day O'Connor, the swing vote on the court.

The conventional version of the '37 tale, a staple of high school and undergraduate history courses, goes something like this: Beginning in 1905, with the Lochner v. New York decision, which struck down a law setting maximum working hours for bakers, the court read into the Constitution a rigid laissez-faire economic worldview. That view stood for 30 years. In the throes of the Depression, as Roosevelt pushed his ambitious legislative agenda to revive the economy, the court struck down law after law, rejecting minimum-wage legislation and gutting the National Industrial Recovery Act and the Agricultural Adjustment Act. Unions and liberal newspapers hammered the court; farmers hanged the justices in effigy.

Then, in early 1937, fresh from his landslide reelection victory, Roosevelt pulled out a club: He proposed to ''pack'' the court-that is, to add one new justice for each one over 70, on the flimsy excuse that the nine justices were overworked (a plan made possible by the fact that the Constitution does not specify how many justices the court should have).

The court caved. In March 1937, less than a year after striking down a very similar law, the justices upheld a minimum-wage law in Washington state, in West Coast Hotel Co. v. Parrish. The key vote, the so-called ''switch'' that ''saved'' the nine, came from Justice Owen Roberts, a frequent ally of the court's four hard-line conservatives. The way was now clear for the Fair Labor Standards Act and Social Security. By 1938, the court had largely removed itself as a block to national economic policy; the world was made safe for the New Deal.

...

That's the story, anyway.

G. Edward White, a law professor and historian at the University of Virginia, calls the tale ''a distortion of the historical record.'' ''The court-packing story is based on a pretty limited base of research,'' he said in an interview. And, he added, ''it's winner's history,'' appealing to people-like liberal historians-who instinctively cast Roosevelt as a hero who imposed his righteous will on hack political judges. The standard narrative, however, has also been accepted by conservatives who think this was the moment constitutional law went off the rails.