If President Obama still wants to turn our economy around, it's time for him to act more like Franklin Roosevelt — but not in the way he might think. It takes a special kind of courage for a president to abandon a failed approach to economic policy and then embrace its opposite. Yet, faced in May 1940 with America's greatest foreign policy crisis since the nation's founding, that's exactly what Franklin D. Roosevelt did. FDR-architect of the New Deal and outspoken opponent of Big Business-was forced by the collapse of Europe's democracies under Hitler's blitzkrieg to turn to the corporate sector to prepare America for war.

Roosevelt had almost no choice. In 1940, the United States had the 18th-largest army in the world, right behind tiny Holland. While not so small, its Navy was totally unprepared to face a determined invader. Gen. George Marshall, Army chief of staff, warned Roosevelt that if Hitler landed five divisions on American soil, there was nothing he could do to stop them.

Neither the War nor Navy Departments had a clue how to mobilize a $100-billion civilian economy for war. Their joint "plan" ran to fewer than 20 typed pages. America's defense industry had been dismantled after World War I-"the war to end all wars."

Arthur Herman is a visiting scholar at AEI.

The full text of this article is available via subscription to The Wall Street Journal. It will be posted to AEI.org on Monday, April 14.