In the last 100 years, only once has a party not won a 2nd consecutive White House term. Obama's approval fluctuations aren't that different from presidents who have won wide re-election margins. The Democrats losing seats next year wouldn't mean much of anything. The Republicans remain deeply unpopular and come across as inept as far as strategy goes. Anything can happen ibut I'd give Obama about a 80-90% chance of re-election at this point regardless of who the Republicans nominate.
Actually, 1912, 1932, 1976, and 1992.
You're incorrect! I believe you misunderstood what he meant though.
When Wilson won in 1912, Republicans had held the White House for four terms (McKinnly, Roosevelt, and Taft)
When FDR won in 1932, Republicans had held the White House for three terms (Harding, Coolige, and Hoover)
And in 1992, Republicans had held the White House for three terms (Reagan, Bush)
The only time a party lost the precidency after just one term, was in 1980 when Reagan defeated Carter.
The fact that it only happened once these last hundred years is a silly reason to think it won't happen this time though.