Palin's hate rallies were enough to make her toxic in the eyes of any rational moderate - and there is no doubt in my mind that she did John McCain a lot of harm with moderate voters
Apparently she did net McCain some votes from the higher base turnout. However, these were probably all in states where McCain could win even with depressed base turnout.
According to Ann Coulter, Palin saved McCain from a 1972 Nixon vs. McGovern style rout. McCain only carried moderate voters in five states: Alabama (49-50); Louisiana (45-54), Alaska (43-55); Oklahoma (43-57) and Wyoming (40-57). McCain lost moderates in his home state of Arizona (52-46)
I don't doubt that she didn't play well with the base of the Republican Party but, nationally, Obama won 20% of the conservative vote. Most of whom were likely conservative Democrats, who tend to be of a more economically populist hue, at least, compared with conservative Republicans
Polling suggests that Obama's recent drop-off in approval seems to be coming from Independents and moderate Republicans. Independents will ebb and flow depending on the extent to which they perceive him performing well, or badly, on the issues that matter to them most. He ran poorly among Southern Independents, generally-speaking, but well among them in the Northeast, Midwest and West - and I suspect the drop-off could be more acute in the more libertarian-minded states he carried like Colorado and Nevada, as well as Arizona and Montana
