All this hero-worship before Mr. Obama met his first test of leadership. In reality, he was who he was, a Chicago politician who had done well by his opposition to the Iraq war. He had run a skillful campaign, and had met a Clinton machine that had run out of tricks and a McCain campaign that never understood the nature of the contest of 2008

He was no FDR, and besides the history of the depression—the real history—bears little resemblance to the received narrative of the nation instantly rescued, in the course of 100 days or 200 days, by an interventionist state. The economic distress had been so deep and relentless that FDR began his second term, in 1937, with the economy still in the grip of recession.

Nor was JFK about style. He had known military service and combat, and familial loss; he had run in 1960 as a hawk committed to the nation's victory in the Cold War. He and his rival, Richard Nixon, shared a fundamental outlook on American power and its burdens.

Now that realism about Mr. Obama has begun to sink in, these iconic figures of history had best be left alone. They can't rescue the Obama presidency. Their magic can't be his. Mr. Obama isn't Lincoln with a BlackBerry.