Highly recommended: Political Arithmetik’s graph and analysis of presidential approval among copartisans, the opposition, and independents. The graph shows low point of overall approval against low point within each partisan component of the electorate.
Just a few observations from my interocular test of the data:
G.W. Bush currently has both the highest approval in the series among partisans and the second lowest among the opposition. (Lowest among opposition was Truman’s amazing 4.5%; Truman, unlike Bush, also fell quite low among copartisans, though not as low as Carter, who holds the copartisan low-approval record by far.)
Opposition approval has little correlation with overall, while approval among independents is almost 1:1 with the overall. The latter, in particular, is perhaps not surprising, given that independents tend to be in the middle, but the near-exact correspondence to overall is striking. There is, however, one data point that is notably off the trend for independents: G.W. Bush. He has a level of approval among independents that is “too low” for his overall approval.
Approval by copartisans is highly correlated, and the slope is quite steep. Naturally, the current president’s defiance of the trend line for independents is a direct result of his also being “too high” among copartisans–in other words, a result of the near imperviousness of Republicans to the contempt with which the rest of their fellow citizens hold their leader.