The Great Depression remains the central economic event in American history. Even today, politicians invoke its memory. For example, Democrats routinely accuse George W. Bush of having economic policies like those of Herbert Hoover, on whose watch the depression began. Given its horrendous effects, accusing anyone of threatening a replay is about as nasty a charge that can be made in politics.

For Democrats, the story line is pretty simple. Republican policies in the 1920s brought on the depression and those of Franklin D. Roosevelt ended it. The former promoted tax cuts and laissez-faire economic policies; the latter raised taxes and instituted broad government regulation of the economy. Therefore, any time a Republican suggests tax cuts or deregulation, we are starting down the road to another depression, in the Democratic playbook. Tax increases and increased regulation, by contrast, are proven methods of preventing and reversing economic stagnation.

Against this, Republicans have never had a good response. In part, that is because some of their policies did in fact cause a lot of the harm that made the depression so long and deep. It was Republican appointees to the Federal Reserve Board in the 1920s that caused the money supply to collapse, thereby initiating a sharp price deflation. It was a Republican Congress and a Republican president who passed the disastrous Smoot-Hawley tariff, which triggered a worldwide trade war that led to a collapse of international trade. They also responded to rising budget deficits resulting from the depression by sharply raising taxes in 1932.

Roosevelt was quite right to attack Hoover during the 1932 campaign for failing to address the problems of deflation, protectionism and high taxes. On the last point, FDR sounded like a modern-day supply-sider in an Oct. 19, 1932 speech. "Taxes are paid in the sweat of every man who labors because they are a burden on production and are paid through production," he said. "If those taxes are excessive, they are reflected in idle factories, in tax-sold farms, and in hordes of hungry people, tramping the streets and seeking jobs in vain."

To try and throw off the legacy of Hoover and eliminate the stigma of causing the Great Depression, some conservatives have sought ways of identifying with Roosevelt. Ronald Reagan often did so, saying that he voted for him 4 times. Newt Gingrich has also praised Roosevelt extravagantly. Now, conservative publisher Conrad Black has come forward with a new book, Franklin D. Roosevelt, Champion of Freedom (Public Affairs, 2003), arguing that Roosevelt was fundamentally a conservative, too.

The book will not be out until next month, but Mr. Black gave a flavor of his argument in a Wall Street Journal article on Oct. 29. The gist of it is that the threat of political revolution in the 1930s is underappreciated. The U.S. could easily have gone the way of many European countries toward state socialism of either the communist or fascist variety. Roosevelt's New Deal kept them at bay, preserving political freedom and the essence of a market economy.

This is actually a familiar argument, although not one that has been made by a conservative before. In the late 1960s, radical historians first put it forward as a leftwing attack on the New Deal. Examples are Barton Bernstein's 1969 essay, "The New Deal: The Conservative Achievements of Liberal Reform," and Ronald Radosh's 1972 article, "The Myth of the New Deal."

Where Mr. Black differs from the left critique of Roosevelt is by adopting the traditional liberal defense of his policies, exemplified by Arthur Schlesinger's 3- vol. history of the Roosevelt administration, and wrapping it in conservative clothing. He defends all of the New Deal economic policies as excellent "crisis management," even though he admits that the actual economics deserve only a "passing grade."

Mr. Black's thesis is plausible and I look forward to reading his analysis in more depth. But I think he too readily excuses Roosevelt's policies as perhaps unhelpful, but not really harmful. Therefore, it should be read together with two other recent histories of that period, Jim Powell's FDR's Folly: How Roosevelt and His New Deal Prolonged the Great Depression (Crown Forum, 2003), and Gene Smiley's Rethinking the Great Depression (Ivan R. Dee, 2002).

Both agree with prominent economic historian Robert Higgs that Roosevelt's policies were far from benign and prevented an economic recovery from taking hold sooner. Higgs goes so far as to call the New Deal "a collection of crackpot policies" that prolonged and deepened the depression, bringing unnecessary suffering to millions.

As the U.S. definitely emerges from its tenth postwar recession, Republicans and Democrats are essentially arguing the same question: did Mr. Bush's policies make it better or worse? Next year, voters will decide. A better understanding of the Great Depression and New Deal may help them do so.