It would take too long to explain all the factors, so I'll just state that what was true for Bush, Sr. is also true for Obama: It's The Economy, Stupid!

Obama has ended DADT. Obama and SEAL Team Six get credit for the death of bin Laden. Obama prevented the Big Three automakers from going under and turning Detroit into the nation's largest ghost town. But the economy is still stuck in the mud, gas prices are still abominable, and nobody seems to be hiring. These factors are all working against Obama and must be dealth with now.