Harvard’s Barry Burden has posted an interesting graphic tracking presidential and Congressional approval during Bush’s time as president:

In analyzing the data, he finds that presidential approval influences Congressional approval, but not the reverse. This result is based on only 56 months of data from one presidency, but it’s an interesting finding. The most obvious implication, of course, is that the same fundamentals — the economy and major foreign policy events — seem to drive both presidential and Congressional approval, a result that’s consistent with the findings presented in Erickson, MacKuen and Stimson’s The Macro Polity.