Almost every time, incumbents either run on their records and win or run from their records and lose. Americans desperate enough to vote for Barack Obama for President because the economy was in a meltdown that began to look like that of 1929-1932 and because America was entangled in costly and increasingly-pointless wars will decide whether he has solved those problems. He succeeded at both, stopping an economic meltdown remarkably similar to the one of nearly eighty years earlier in the equivalent of the Spring of 1931 instead of the Autumn of 1932. What he couldn't do is to stop the slander machine of ideologues who want America to work only for an elite nearly devoid of virtues.
For two years President Obama did as much as was possible to apply Keynesian stimulus to an economic meltdown... and that stimulus worked. The meltdown stopped. President Obama saved the system from catastrophic failure even if such meant the rescue of Big Business. The investment went back into the economy largely as taxable income. Just think of what would have happened to tax revenues had America undergone a concatenation of business failures as those from the summer of 1931 to the autumn of 1932. Beginning in 2011 President Obama has had to rely upon monetarist methods to keep the economy going -- because monetarist methods don't require legislative approval.
The last incumbent President to run from his record was Jimmy Carter, and we well know how that worked. Jimmy Carter may have been the least effective President since Herbert Hoover as shown in the paucity of his legislative achievements. When he ran for re-election he had to make fresh promises of what he would do in a second term and effectively gave up the usual advantage of an incumbent (as if that hadn't been taken away from him) while Ronald Reagan offered tried-and-true measures (or at least presented them as such) that Americans thought that they wanted. Reagan won.
Right-wingers might wish to see Barack Obama as the new Jimmy Carter... but unlike Jimmy Carter he has a rich record of legislative achievements when he had majorities in both Houses of Congress. Carter achieved little with such majorities. President Obama can show that the international scene is safer than it was -- the opposite of how things were under Carter.
President Obama is above all else a student of history. He may admire Abraham Lincoln -- but he may end up more like Harry Truman. After all, President Obama is a Reactive/Nomad, as shown in the gangland-style hit on Osama bin Laden (the style is that of Al Capone even if the purpose is honorable). If he is to be an effective President in a second term he will need majorities in both Houses of Congress. I can already predict that he will run against a Congress that has achieved little except to offer extremist solutions. The Truman analogy isn't perfect:
Here is the source.
But if the undistinguished 80th Congress failed to achieve the somewhat-progressive promises that Tom Dewey stood for in his campaign, the dreadful 112th Congress offers little. The House is in the hands of reactionaries more intent on undoing the current Presidency and perhaps a century of social advance and even such personal freedom as reproductive rights.
President Obama is a student of history, and if he can't be a Lincoln he can at least be a Truman... but Truman is generally understood to be one of the strongest Presidents that we ever had.