In the 210 years of the American presidency, only two new presidents have arguably faced challenges of the magnitude that confronts Barack Obama: Lincoln and FDR. Yet Obama may be subject to higher expectations than either of those legendary predecessors. When Lincoln acceded to the presidency as the union threatened to dissolve, he did so largely thanks to a schism among the Democrats. The Great Emancipator was thought by many to be a lucky beneficiary of the crisis that did in his opponents; few gave him credit for a masterful campaign. For many months after he entered the White House, the weight of "informed" opinion continued to underestimate him.
FDR was the subject of great hopes, but no one could have expected him to perform as he did, not least because no government in the history of the world had ever acted on such a scale or with so much sustained energy as America (and the world) saw during Roosevelt's four terms. Notably, Roosevelt in office was far more innovative and energetic than FDR the candidate had suggested he would be.
Obama suffers--yes, suffers--because he has predecessors such as Roosevelt and Lincoln. I have suggested, only half in jest, that every 150 years or so the nation needs a tall, skinny guy from Illinois. The challenges that we must meet now are easily analogized to those of 1933. But unlike FDR and Lincoln, we have the example of those great forebears with which to compare Barack Obama. (I am not aware that FDR was widely compared with Lincoln in 1932 or 1933; the crises that contronted the two men were almost entirely different.)
The presidency is a crushing burden. The expectations that confront Obama can only make it more so. Let's hope and even pray (even if you are not religious, dear reader, what could it hurt?) that our forty-fourth President can stand up and ever excel, under the pressure.