Once a single political party comes to dominate national government, it begins to lose support. Today's Democrats are no exception to this trend; in fact, they have lost support at a quicker pace than usual. Just why this happens is explained well by political scientist James Stimson in his book "Tides of Consent: How Public Opinion Shapes American Politics" (Cambridge, 2004).
Stimson finds that the overall public mood about government starts to run counter to victorious political parties soon after they win. Voters typically elect Democrats when a liberal, pro-activist federal government sentiment peaks. After that, sentiment starts to shift in a more conservative direction. The same happens in reverse once Republicans win control of government--public opinion shifts in favor of bigger government.
Stimson finds that three groups of approximately equal size comprise the electorate: the Passionate, the Scorekeepers and the Uninvolved.
The Passionate stick with their respective parties regardless of events. The Uninvolved shift, but randomly and their changes tend to cancel each other out. The Scorekeepers, Stimson writes, "[pay] enough attention to respond to common signals of politics, yet...[are] not so involved as to be committed always to one side. They produce all of our evidence of systematic change."
Stimson argues these shifts "should not be understood as an emotional rejection or a 'backlash,' but as more mundane, saying in essence, 'Okay, we've had a big change in direction. That's enough.'"
Weekly Standard blogger Gary Andres, reflecting on Stimson's findings, recently noted that "Shifts in political mood occur for a lot of reasons. The economy and presidential approval are among the most important. Yet the changing perception of the Scorekeepers also plays a role."
So how will the scorekeepers respond in 2010? Probably against the Democrats if Stimson's findings are any guide.