But paradoxically, Obama’s surprise victory in those red states means that he could have a tough hill to climb in 2012. Almost uniformly, presidential candidates either improve on their original victory total — or they lose. What they don’t do is win with fewer Electoral College or popular votes than they received the first time around. For presidents seeking re-election, the rule has been simple: “Do better or get out.”

The historical numbers tell the tale. Twenty-four presidents have sought and received their party’s nomination for re-election; 15 of them won. Of those 15, only one — Woodrow Wilson — received fewer electoral votes in his re-election campaign and still managed to win re-election. And only Andrew Jackson may have received a smaller percentage of the popular vote in his re-election campaign — although, back when Jackson was re-elected, not all states counted popular votes, so it’s hard to say for sure.

Anyone who took high school history realizes that Wilson’s electoral numbers get a major asterisk. In his original election in 1912, Wilson was running in a three-person race against Teddy Roosevelt and William Howard Taft, who split the Republican vote and allowed Wilson to rack up what was at the time one of the largest Electoral College margins in history. Wilson barely squeaked by in his re-election run in 1916, triumphing in no small part because of a feud between Charles Evans Hughes, the Republican nominee, and Hiram Johnson, the governor of California.