The conventional wisdom in this country is that incumbent Presidents effectively just don't lose short of some freak events, such that in 2012 we should go in expecting defeat. That's not the case. While it is true that in 2012 we will start off behind President Obama, the historical advantage of incumbency is not insurmountable. Especially if the President receives a serious primary challenge, we should go into the election expecting to beat him, not merely to contain losses downticket.
|1948||Truman||W||Y*||Succeeded as VP, No primaries but party bosses attempted replacement, Democrats split on racism with third party taking 39 EVs|
|1964||Johnson||W||N||Succeeded as VP|
|1968||Johnson||L||Y||Effectively a third term, Democrats split on war and racism with third party taking 46 EVs|
|1976||Ford||L||Y||Unelected, Succeeded as VP|
|1992||GHW Bush||L||Y||Republican split in taxes, independent takes 19% of popular vote|
I've classed these Presidential runs by incumbents in two broad categories: The first category is with the light backgrounds and includes three elections of the post-war era: 1948, 1964, and 1976. These incumbents were not elected President. In them, the incumbents go 2-1. Johnson faced no serious opposition for the Democrat nomination and cruised to victory. Truman and Ford did not have their nominations assured, and both had close races, going 1-1.
The second category includes all other incumbents who took office by running for President and winning. In the post-war era these incumbents go 5-3, with all three losers suffering serious party challenges. In Johnson 1968's case, he had no serious chance of winning the nomination against the Communist-driven pacifist movement sweeping his party.
I conclude we'd best hope President Obama receives a primary challenge, because historically the President's own party members are excellent at sensing weakness in an incumbent's re-election chances. Does anyone have the ear of Secretary Clinton, or perhaps a candidate who can capitalize on Democrat dissatisfaction over war and rendition for torture?