1) The unemployment rate technically goes down, but that's because the US government continues to game the statistics to include less people through seasonal adjustment and no longer counting the jobless after a certain amount of time. The real rate is substantially higher than reported, to the point that people stop taking the government seriously.
2) Europe experiences more dramatic economic problems, resulting in a short term move towards the dollar. Commodities in the US stabilize somewhat, despite some arguing that debt deflation is now an inevitability.
3) Palin continues to move away from Bush era foreign policy and some of her previous statements as usual.
4) Crime becomes more of a problem sparking more of a backlash among white voters.
5) Turn out is generally low, and that combined with the above results in the white vote being proportionally larger than usual.
6. Palin winds up winning substantially as a result of all the above factors plus general cynicism over the media's perceived cosiness with Obama, with the perception being anyone so unpopular can't be that bad.
Ron Paul vs Barack Obama.