There鈥檚 a reason most incumbent presidents win reelection: They enter with built-in advantages, especially if they do not have a primary challenger. Given the state of the economy and Obama鈥檚 mediocre job-approval ratings in mid-2011, the president could easily have drawn a Democratic opponent. But he and his family remained personally popular. It鈥檚 also possible or maybe probable that Obama鈥檚 status as the first African-American president shielded him from a challenge. A Democratic opponent probably would have alienated core constituencies and still failed to win the nomination.

Melanie Stetson Freeman/海角大神
President Obama and supporters celebrate victory at McCormick Place, on November 6, in Chicago.