Purple State Extremism? How Two-Party States Polarize

Many Americans believe national politics are more polarized than ever. The common narrative is that Americans increasingly self-segregate their neighborhoods, media consumption, and even dating lives along partisan lines. This self-sorting creates enclaves of like-minded Americans — “red” and “blue” neighborhoods, counties, and states. As a result, voters elect politically extreme legislators who pander to their bases, further polarizing the nation.

However, a paper published in The Journal of Politics by the University of California at Berkeley’s Neil O’Brian casts doubt on that explanation. Americans may presume that present politics are uniquely polarized between “red” and “blue,” but the reality is not so simple.

O’Brian points out that the past two decades have seen parties competing over more states than in the past, resulting in fewer “red” and “blue” states and more “purple” states. “Perhaps counterintuitively,” he writes, “average party competition in the US states in the 1990s and 2000s, an era of intense polarization, has been higher than at any point since Reconstruction.” During the 1920s, more than 30 percent of Congress members were elected to Congress from states where one party controlled more than 90 percent of legislative seats. Today, only a single state, Hawaii, exhibits such extreme one-party dominance. Accordingly, and contrary to the popular narrative, the number of states hosting competitive congressional elections over the past two decades has risen.

If one-party dominance is on the decline, why does it feel like polarization is growing? O’Brian links his first finding — increased competition — with a second surprising finding: “purple” states elect legislators who are, on average, more extreme than their typical party colleagues. In states where parties compete fiercely, parties choose their nominees in ideologically unrepresentative primaries. Having selected ideologically extreme nominees, the parties must continue to use strong ideology to mobilize their voters in general elections. The resulting winners in these “competitive” states are more extreme than the median voter.

In contrast, one-party dominance replaces competition between parties with competition within parties. In these states, electoral competition is generally limited to primaries. Because the dominant party is “the only game in town,” minority-party and moderate voters participate in the dominant party’s primaries. This pulls the nominees toward the center and away from the extremes. Moreover, without competition, dominant parties lose the need to mobilize voters ideologically. The result is more moderate general election candidates.

For instance, Republican representatives from Alabama and California are indistinguishable from each other by measures of ideology, despite the GOP’s dominance in the former and minority status in the latter. Sometimes this can lead to even more surprising phenomena. Over the past decade, intraparty conflict between moderates and radicals in single-party states has become so intense that majority-party moderates have aligned themselves with minority party legislators to govern state legislatures.

O’Brian’s research finds this phenomenon to be true over different periods of time and across different regions of the United States. In the post-Reconstruction South, for instance, politics were dominated by the Democratic Party from the end of Reconstruction in the 1870s until the Civil Rights Era in the 1960s. State-level Democratic parties were united by a commitment to white supremacy but little else. On a national level, local Democratic dominance resulted in elected legislators who defected from the party majority more frequently. The same was true of Republican legislators elected from the great plains and mountain west during the period. In each case, the dominant party’s catch-all nature resulted in congressional delegations that were more “moderate” than their respective national parties, measured by common metrics of congressional ideologies.

As a whole, O’Brian’s research suggests that polarization and competition may be two sides of the same coin. Policies that aim to increase competition may only increase political polarization. Advocates of electoral reform may believe that policies such as non-partisan redistricting and campaign finance reform are good things in and of themselves but should not presume such measures will reduce legislative polarization.

Article source: Neil A. O’Brian, “One-Party States and Legislator Extremism in the US House, 1876–2012,” The Journal of Politics 81, no. 4 (October 2019): 1223-1239.