Government » American Political Parties » Divided Government and Partisan Polarization

The Causes Of Polarization

The Causes of Polarization

Scholars agree that some degree of polarization is occurring in the United States, even if some contend it is only at the elite level. But they are less certain about exactly why, or how, polarization has become such a mainstay of American politics. Several conflicting theories have been offered. The first and perhaps best argument is that polarization is a party-in-government phenomenon driven by a decades-long sorting of the voting public, or a change in party allegiance in response to shifts in party position. According to the sorting thesis, before the 1950s, voters were mostly concerned with state-level party positions rather than national party concerns. Since parties are bottom-up institutions, this meant local issues dominated elections; it also meant national-level politicians typically paid more attention to local problems than to national party politics.

But over the past several decades, voters have started identifying more with national-level party politics, and they began to demand their elected representatives become more attentive to national party positions. As a result, they have become more likely to pick parties that consistently represent national ideals, are more consistent in their candidate selection, and are more willing to elect office-holders likely to follow their party’s national agenda. One example of the way social change led to party sorting revolves around race.

The Democratic Party returned to national power in the 1930s largely as the result of a coalition among low socio-economic status voters in northern and midwestern cities. These new Democratic voters were religiously and ethnically more diverse than the mostly white, mostly Protestant voters who supported Republicans. But the southern United States (often called the “Solid South”) had been largely dominated by Democratic politicians since the Civil War. These politicians agreed with other Democrats on most issues, but they were more evangelical in their religious beliefs and less tolerant on racial matters. The federal nature of the United States meant that Democrats in other parts of the country were free to seek alliances with minorities in their states. But in the South, African Americans were still largely disenfranchised well after Franklin Roosevelt had brought other groups into the Democratic tent.

The Democratic alliance worked relatively well through the 1930s and 1940s when post-Depression politics revolved around supporting farmers and helping the unemployed. But in the late 1950s and early 1960s, social issues became increasingly prominent in national politics. Southern Democrats, who had supported giving the federal government authority for economic redistribution, began to resist calls for those powers to be used to restructure society. Many of these Democrats broke away from the party only to find a home among Republicans, who were willing to help promote smaller national government and greater states’ rights. This shift was largely completed with the rise of the evangelical movement in politics, when it shepherded its supporters away from Jimmy Carter, an evangelical Christian, to Ronald Reagan in the 1980 presidential election.

At the same time social issues were turning the Solid South towards the Republican Party, they were having the opposite effect in the North and West. Moderate Republicans, who had been champions of racial equality since the time of Lincoln, worked with Democrats to achieve social reform. These Republicans found it increasing difficult to remain in their party as it began to adjust to the growing power of the small government–states’ rights movement. A good example was Senator Arlen Specter, a moderate Republican who represented Pennsylvania and ultimately switched to become a Democrat before the end of his political career.

A second possible culprit in increased polarization is the impact of technology on the public square. Before the 1950s, most people got their news from regional newspapers and local radio stations. While some national programming did exist, most editorial control was in the hands of local publishers and editorial boards. These groups served as a filter of sorts as they tried to meet the demands of local markets.

As described in detail in the media chapter, the advent of television changed that. Television was a powerful tool, with national news and editorial content that provided the same message across the country. All viewers saw the same images of the women’s rights movement and the war in Vietnam. The expansion of news coverage to cable, and the consolidation of local news providers into big corporate conglomerates, amplified this nationalization. Average citizens were just as likely to learn what it meant to be a Republican from a politician in another state as from one in their own, and national news coverage made it much more difficult for politicians to run away from their votes. The information explosion that followed the heyday of network TV by way of cable, the Internet, and blogs has furthered this nationalization trend.

A final possible cause for polarization is the increasing sophistication of gerrymandering, or the manipulation of legislative districts in an attempt to favor a particular candidate. According to the gerrymandering thesis, the more moderate or heterogeneous a voting district, the more moderate the politician’s behavior once in office. Taking extreme or one-sided positions on a large number of issues would be hazardous for a member who needs to build a diverse electoral coalition. But if the district has been drawn to favor a particular group, it now is necessary for the elected official to serve only the portion of the constituency that dominates.

A cartoon that depicts gerrymandering. The outline of several voting districts is shown. The border of the districts is used as the backbone for a large fantastical creature.

This cartoon, which inspired the term gerrymander, was printed in the Boston Gazette on March 26, 1812, after the Massachusetts legislature redistricted the state to favor the party of the sitting governor, Elbridge Gerry.

Gerrymandering is a centuries-old practice. There has always been an incentive for legislative bodies to draw districts in such a way that sitting legislators have the best chance of keeping their jobs. But changes in law and technology have transformed gerrymandering from a crude art into a science. The first advance came with the introduction of the “one-person-one-vote” principle by the U.S. Supreme Court in 1962. Before then, it was common for many states to practice redistricting, or redrawing of their electoral maps, only if they gained or lost seats in the U.S. House of Representatives. This can happen once every ten years as a result of a constitutionally mandated reapportionment process, in which the number of House seats given to each state is adjusted to account for population changes.

But if there was no change in the number of seats, there was little incentive to shift district boundaries. After all, if a legislator had won election based on the current map, any change to the map could make losing seats more likely. Even when reapportionment led to new maps, most legislators were more concerned with protecting their own seats than with increasing the number of seats held by their party. As a result, some districts had gone decades without significant adjustment, even as the U.S. population changed from largely rural to largely urban. By the early 1960s, some electoral districts had populations several times greater than those of their more rural neighbors.

However, in its one-person-one-vote decision in Reynolds v. Simms (1964), the Supreme Court argued that everyone’s vote should count roughly the same regardless of where they lived. Districts had to be adjusted so they would have roughly equal populations. Several states therefore had to make dramatic changes to their electoral maps during the next two redistricting cycles (1970–1972 and 1980–1982). Map designers, no longer certain how to protect individual party members, changed tactics to try and create safe seats so members of their party could be assured of winning by a comfortable margin. The basic rule of thumb was that designers sought to draw districts in which their preferred party had a 55 percent or better chance of winning a given district, regardless of which candidate the party nominated.

Of course, many early efforts at post-Reynolds gerrymandering were crude since map designers had no good way of knowing exactly where partisans lived. At best, designers might have a rough idea of voting patterns between precincts, but they lacked the ability to know voting patterns in individual blocks or neighborhoods. They also had to contend with the inherent mobility of the U.S. population, which meant the most carefully drawn maps could be obsolete just a few years later. Designers were often forced to use crude proxies for party, such as race or the socio-economic status of a neighborhood. Some maps were so crude they were ruled unconstitutionally discriminatory by the courts.

A series of three maps titled Gerrymandering in Austin, Texas, 2003–2015

Examples of gerrymandering in Texas, where the Republican-controlled legislature redrew House districts to reduce the number of Democratic seats by combining voters in Austin with those near the border, several hundred miles away. Today, Austin is represented by six different congressional representatives.

Proponents of the gerrymandering thesis point out that the decline in the number of moderate voters began during this period of increased redistricting. But it wasn’t until later, they argue, that the real effects could be seen. A second advance in redistricting, via computer-aided map making, truly transformed gerrymandering into a science. Refined computing technology, the ability to collect data about potential voters, and the use of advanced algorithms have given map makers a good deal of certainty about where to place district boundaries to best predetermine the outcomes. These factors also provided better predictions about future population shifts, making the effects of gerrymandering more stable over time. Proponents argue that this increased efficiency in map drawing has led to the disappearance of moderates in Congress.

According to political scientist Nolan McCarty, there is little evidence to support the redistricting hypothesis alone. First, he argues, the Senate has become polarized just as the House of Representatives has, but people vote for Senators on a statewide basis. There are no gerrymandered voting districts in elections for senators. Research showing that more partisan candidates first win election to the House before then running successfully for the Senate, however, helps us understand how the Senate can also become partisan. Furthermore, states like Wyoming and Vermont, which have only one Representative and thus elect House members on a statewide basis as well, have consistently elected people at the far ends of the ideological spectrum. Redistricting did contribute to polarization in the House of Representatives, but it took place largely in districts that had undergone significant change.

Furthermore, polarization has been occurring throughout the country, but the use of increasingly polarized district design has not. While some states have seen an increase in these practices, many states were already largely dominated by a single party (such as in the Solid South) but still elected moderate representatives. Some parts of the country have remained closely divided between the two parties, making overt attempts at gerrymandering difficult. But when coupled with the sorting phenomenon discussed above, redistricting probably is contributing to polarization, if only at the margins.

The Politics of Redistricting

Voters in a number of states have become so worried about the problem of gerrymandering that they have tried to deny their legislatures the ability to draw district boundaries. The hope is that by taking this power away from whichever party controls the state legislature, voters can ensure more competitive districts and fairer electoral outcomes.

In 2000, voters in Arizona approved a referendum that created an independent state commission responsible for drafting legislative districts. But the Arizona legislature fought back against the creation of the commission, filing a lawsuit that claimed only the legislature had the constitutional right to draw districts. Legislators asked the courts to overturn the popular referendum and end the operation of the redistricting commission. However, the U.S. Supreme Court upheld the authority of the independent commission in a 5–4 decision titled Arizona State Legislature v. Arizona Independent Redistricting Commission (2015).

Currently, only five states use fully independent commissions—ones that do not include legislators or other elected officials—to draw the lines for both state legislative and congressional districts. These states are Arizona, California, Idaho, Montana, and Washington. In Florida, the League of Women Voters and Common Cause challenged a new voting districts map supported by state Republicans, because they did not believe it fulfilled the requirements of amendments made to the state constitution in 2010 requiring that voting districts not favor any political party or incumbent.

Do you think redistricting is a partisan issue? Should commissions draw districts instead of legislators? If commissions are given this task, who should serve on them?

Think you have what it takes to gerrymander a district? Play the redistricting game and see whether you can find new ways to help out old politicians.

[Attributions and Licenses]


This is a lesson from the tutorial, American Political Parties and you are encouraged to log in or register, so that you can track your progress.

Log In

Share Thoughts