George W. Bush has provoked the widest partisan differences in popular evaluations of a president's performance ever observed in the nearly seven decades that the surveys have been asking the job approval question. (1) In a new book explaining why Bush has become such a divisive figure, I argue that, while the polarized political atmosphere he inherited was a contributing factor, Bush's leadership style, agenda, tactics, strategies, and policy decisions (most notably, to invade Iraq) are the main reasons he has leapt far ahead of his closest competitors, Ronald Reagan and Bill Clinton, to become the most polarizing president on record (Jacobson 2006).
It is clear from Bush's example that presidents do much to shape how they are perceived by their own and the other party's identifiers and therefore how far they polarize the public. This should be true of other politicians as well. Hard-line ideologues, for example, ought to provoke more divergent reactions than moderate centrists. Politicians who lead or stand loyally with their parties on the fundamental issues that divide Democrats and Republicans ought to be more polarizing than party mavericks or those who keep low national profiles and busy themselves delivering local benefits. Context and agendas should also matter. Politicians holding office at the national level, where the parties have become sharply divided across a range of issues, should find it harder to attract bipartisan approval than those serving at the state level, where the agenda (not to mention the local political ethos) may not encourage sharp partisan divisions. And, because they can cultivate personal connections with a larger share of their electorates, politicians serving relatively small, homogeneous populations should find it easier to reach across party lines than should those serving large, heterogeneous populations.
Data to test these hypotheses, and, more generally, to compare partisan differences in evaluations of President Bush to those for other prominent elected officials, have recently become available. Beginning in May 2005, SurveyUSA, a polling firm whose main clients for its political surveys are local news media, has been conducting monthly statewide polls in all fifty states. Their automated telephone surveys ask samples of approximately six hundred respondents in each state whether they approve of the performance of G. W. Bush, the state's governor, and both of its senators, as well as questions about each respondent's party identification, ideology, religious service attendance, and demographic characteristics (age, education, sex, race, and in some states, region). In some months they also ask respondents' positions on policy issues. The aggregate results, including breakdowns of the approval questions by all of the respondents' other characteristics, are posted on the Internet shortly after the surveys are taken. (2) Obviously, such data are potentially of great value for addressing a variety of interesting questions about state-level public opinion and elections--if they are of sufficient quality to be reliable. I thus examined the data carefully for internal and external consistency as well as intuitive plausibility and, as I describe in the Appendix, they passed all of the tests very satisfactorily. For the analyses that follow, I use the data produced by the nine monthly surveys taken from May 2005 through January 2006.
Comparing Performance Approval Ratings
I began by comparing the means and distributions of job approval ratings across states for the three offices. I expected greater dispersal for senators and governors than for the president, if only because I was comparing evaluations of a single individual to those of 50 (governors) or 100 (senators) separate officeholders. Figure 1, which displays the kernel density plots of approval levels across states for all nine monthly surveys, confirms this expectation, but barely in the case of senators. …