For more than 30 years, Abramowitz and Saunders note, the American National Election Studies (NES) survey has asked voters whether they approve of the incumbent president. "According to data from the 2004 NES survey, 90 percent of Republican identifiers approved of Bush's performance and 66 percent approved strongly; in contrast, 81 percent of Democratic identifiers disapproved of Bush's performance and 64 percent disapproved strongly. Evaluations of George W. Bush were more divided along party lines than those of any president since the NES began asking the presidential approval question in 1972."
Yet Abramowitz and Saunders offer some perspective: "The highly polarized evaluations of George Bush in 2004 were not unique--they represented a continuation of a trend that goes back several decades: the difference between the percentage of Democratic identifiers approving of the president's performance and the percentage of Republican identifiers approving of the president's performance was 36 points for Richard Nixon in 1972, 42 points for Jimmy Carter in 1980, 52 points for Ronald Reagan in 1988, 55 points for Bill Clinton in 1996, and 71 points for George W. Bush in 2004."
Using the results of the NES "issue questions," Abramowitz and Saunders devised a seven-point scale to measure ideological polarization. "The percentage of respondents at the low end of the polarization scale fell from 39 percent during the 1980s to 32 percent in 2002-2004 while the percentage at the high end rose from 24 percent to 33 percent," they report. "These results indicate that ideological thinking is more prevalent among the American public today than in the past."
They also find evidence of a growing correlation between ideology and party identification, which has led to a spike in partisan polarization. "Between 1972 and 2004, the difference between the mean score of Democratic identifiers and the mean score of Republican identifiers on the seven-point liberal-conservative identification scale doubled from 0.9 units to 1.8 units. Given the limited range of this scale--the standard deviation was 1.46 in 2004--this is a substantial increase in polarization."
What's more, polarization tends to rise in tandem with political engagement. "It is mainly the least interested, least informed, and least politically active members of the public who are clustered near the center of the ideological spectrum," Abramowitz and Saunders write. "The most interested, informed, and active citizens are much more polarized in their political views." In other words, even if the 2008 election campaign spurs a rise in political participation, it may not reverse the cycle of polarization.
Which brings us back to Obama. Despite his talk of transcending partisanship, he is hardly running on a centrist, bipartisan policy agenda. According to the National Journal rankings, Obama had the most liberal voting record of any U.S. senator in 2007. When he attacks Hillary Clinton, he typically does so from the left (on Iraq and Iran, for example). Obama already seems to understand the limits of "post-partisanship" quite well.
Duncan Currie is managing editor of The American.