Election outcomes are mostly determined by the fundamentals rather than by the candidates or the campaigns. And as you can see in Gallup's polling data above the fundamentals are good. They further observe that "The Democratic advantage is even greater when taking into account the partisan leanings of independents . . . 11-point gap in partisan leaning is the largest Gallup has observed since it began regularly measuring partisan leanings in 1991, topping the previous high gap of 10.2 points from last year . . . Democrats not only maintained but increased their partisanship advantage over the Republicans in 2007, at a time when the ranks of independents were also swelling in the mid-phase of the two-year party ID cycle."