Splits along parties lines:
John Sides estimates what would happen if Obama and Bush were blamed equally:
First, Obama’s job approval would decline by about 11 points. Second, his poll standing relative to Romney’s would decline by 3 points. Both of these declines are statistically significant and substantively important. To be sure, this exercise is purely hypothetical. Life isn’t a laboratory, and we can’t replay Obama’s first 3 years and have voters blame him less or more than they do in reality. Nevertheless, Obama’s lead in the blame game appears to be helping him in the horserace.