In politics, polarization (or polarisation) can refer to the divergence of political attitudes to ideological extremes. Almost all discussions of polarization in political science consider polarization in the context of political parties and democratic systems of government. When polarization occurs in a two-party system, like the United States, moderate voices often lose power and influence.
Definitions and measurementsEdit
Political polarization refers to the cases in which an individual's stance on a given issue, policy, or person is more likely to be strictly defined by their identification with a particular political party (e.g., Democrat or Republican) or ideology (e.g., liberal or conservative). According to DiMaggio et al. (1996), "Polarization is both a state and a process. Polarization as a state refers to the extent to which opinions on an issue are opposed in relation to some theoretical maximum. Polarization as a process refers to the increase in such opposition over time." Some political scientists argue that polarization requires divergence on a broad range of issues based on a consistent set of beliefs. Others argue polarization occurs when there are stark partisan or ideological divides, even if the opinion is polarized only on a few issues.
Political scientists typically distinguish between two types of political polarization: elite polarization and popular polarization. "Elite polarization" refers to the polarization of political elites, like party organizers and elected officials, while "popular polarization" (or mass polarization) refers to the polarization in the electorate and general public. In either context, opinions and policy positions are characterized by strict adherence to party lines. Elite polarization and popular polarization can occur at the same time or independent of each other. A central issue in the study of political polarization is investigating the relationship between elite polarization and popular polarization, particularly any causal relationships between the two.
Elite polarization refers to polarization in the party-in-government and party-as-organization. It occurs when party members (both elected government officials and activists within the party organization itself) grow more internally homogenous on policy positions and more divergent relative to members of other parties. Polarized political parties are internally cohesive, unified, programmatic, and ideologically distinct; they are typically found in a parliamentary system of democratic governance.
In a two-party system like the U.S., a polarized legislature has two important characteristics: first, there is little-to-no ideological overlap between members of the two parties; and second, almost all conflict over legislation and policies is split across the broad liberal/conservative ideological divide. This leads to the conflation of political parties and ideologies (i.e., Democrat and Republican become nearly perfect synonyms for liberal and conservative) and the collapse of the ideological center.
The vast majority of studies on elite polarization focus on legislative and deliberative bodies. For many years, political scientists measured polarization by examining the ratings of party members published by interest groups, but now, most analyze roll-call voting patterns to determine trends in party-line voting and party unity. Many political scientists studying American politics rely on Poole and Rosenthal's DW-NOMINATE scores, which assign a single liberal-conservative score to each congressperson, enabling comparisons of members from different Congresses. There is much more research on polarization in Congress than on polarization in the other branches of government or in state governments. Azzimonti's political polarization index is more comprehensive instead because it is based on media coverage of newspaper articles reporting political disagreement about policy in all branches of government. Recent work by Gentzkow, Shapiro, and Taddy has used the text of the Congressional Record to document differences in speech patterns between Republicans and Democrats as a measure of polarization. They find that polarization has increased dramatically since 1994.
Popular polarization, or mass polarization, occurs when the electorate's attitudes towards political issues, policies, and people are starkly divided along partisan lines. Members of the electorate and general public typically become less moderate in cases of popular polarization. In the U.S., media accounts typically simplify popular polarization to a divide between red states and blue states or a "culture war" between values-voters and progressives. Political scientists, though, generally agree that such accounts are too simplistic and ignore the complex factors that can account for polarization. Many political scientists consider political polarization a top-down process, in which elite polarization leads to – or at least precedes – popular polarization.  However, polarization among elites does not necessarily produce polarization within the electorate, and polarized electoral choices can often reflect elite polarization rather than voters' preferences.
Political scientists studying popular polarization typically rely on data from opinion polls and election surveys. They look for trends in respondents' opinions on a given issue, their voting history, and their political ideology (conservative, liberal, moderate, etc.), and they try to relate those trends to respondents' party identification and other potentially polarizing factors (like geographic location or income bracket). Political scientists typically limit their inquiry to issues and questions that have been constant over time, in order to compare the present day to what the political climate has historically been. Oft-cited public opinion polls in the U.S. include those run by the Pew Research Center and Gallup, Inc., while political scientists also rely on more academic surveys, like the General Social Survey and the election surveys and "feeling thermometer" polls conducted by National Election Studies.
Some scholars argue that diverging parties has been one of the major driving forces of polarization as policy platforms have become more distant. This theory is based on recent trends in the United States Congress, where the majority party prioritizes the positions that are most aligned with its party platform and political ideology. The adoption of more ideologically distinct positions by political parties can cause polarization among both elites and the electorate. For example, after the passage of the Voting Rights Act, the number of conservative Democrats in Congress decreased, while the number of conservative Republicans increased. Within the electorate during the 1970s, Southern Democrats shifted toward the Republican Party, showing polarization among both the elites and the electorate of both main parties.
Political scientists have shown politicians have an incentive to advance and support polarized positions. These argue that during the early 1990s, the Republican Party used polarizing tactics to become the majority party in the United States House of Representatives—which political scientists Thomas E. Mann and Norman Ornstein refer to as Newt Gingrich's "guerrilla war." What political scientists have found is that moderates are less likely to run than are candidates who are in line with party doctrine, otherwise known as "party fit."Other theories state politicians who cater to more extreme groups within their party tend to be more successful, helping them stay in office while simultaneously pulling their constituency toward a polar extreme. A study by Nicholson (2012) found voters are more polarized by contentious statements from leaders of the opposing party than from the leaders of their own party. As a result, political leaders may be more likely to take polarized stances.
With regards to multiparty systems, Giovanni Sartori (1966, 1976) claims the splitting of ideologies in the public constituency causes further divides within the political parties of the countries. He theorizes that the extremism of public ideological movement is the basis for the creation of highly polarized multiparty systems. Sartori named this polarizing phenomenon polarized pluralism and claimed it would lead to further polarization in many opposing directions (as opposed to in simply two directions, as in a polarized two-party system) over policy issues. Polarization in multiparty systems can also be defined along two ideological extremes, like in the case of India in the 1970s. Ideological splits within a number of India's major parties resulted in two polarized coalitions on the right and left, each consisting of multiple political parties.
Political fund-raisers and donors can also exert significant influence and control over legislators. Party leaders are expected to be productive fund-raisers, in order to support the party's campaigns. After Citizens United v. Federal Election Commission, special interests in the U.S. were able to greatly impact elections through increased undisclosed spending, notably through Super political action committees. Some, such as Washington Post opinion writer Robert Kaiser, argued this allowed wealthy people, corporations, unions, and other groups to push the parties' policy platforms toward ideological extremes, resulting in a state of greater polarization. Other scholars, such as Raymond J. La Raja and David L. Wiltse, note that this does not necessarily hold true for mass donors to political campaigns. These scholars argue a single donor who is polarized and contributes large sums to a campaign does not seem to usually drive a politician toward political extremes.
In democracies and other representative governments, citizens vote for the political actors who will represent them. Some scholars argue that political polarization reflects the public's ideology and voting preferences. Dixit and Weibull (2007) claim that political polarization is a natural and regular phenomenon. They argue that there is a link between public differences in ideology and the polarization of representatives, but that an increase in preference differences is usually temporary and ultimately results in compromise.
Morris P. Fiorina (2006, 2008) posits the hypothesis that polarization is a phenomenon which does not hold for the public, and instead is formulated by commentators to draw further division in government. Other studies indicate that cultural differences focusing on ideological movements and geographical polarization within the United States constituency is correlated with rises in overall political polarization between 1972 and 2004.
Religious, ethnic, and other cultural divides within the public have often influenced the emergence of polarization. According to Layman et al. (2005), the ideological split between U.S. Republicans and Democrats also crosses into the religious cultural divide. They claim that Democrats have generally become more moderate in religious views whereas Republicans have become more traditionalist. For example, political scientists have shown that in the United States, voters who identify as Republican are more likely to vote for a strongly evangelical candidate than Democratic voters. This correlates with the rise in polarization in the United States. Another theory contends that religion does not contribute to full-group polarization, but rather, coalition and party activist polarization causes party shifts toward a political extreme.
In some post-colonial countries, the public may be polarized along ethnic divides that remain from the colonial regime. In South Africa in the late 1980s, members of the conservative, pro-apartheid National Party of South Africa were no longer supportive of apartheid, and, therefore, no longer ideologically aligned with their party. Dutch Afrikaners, white English, and native Africans split based on racial divisions, causing polarization along ethnic lines.
Economic inequality can also motivate the polarization of the public. For example, in post-World War I Germany, the Communist Workers Party, and the National Socialists, a fascist party, emerged as the dominant political ideologies and proposed to address Germany's economic problems in drastically different ways. In Venezuela in the late 20th century, the entrance of the oil industry into the local economy caused economic disparities that led to sharp ideological divides. As a result, the disenfranchised working class aligned with extreme socialist leader Hugo Chávez.
The impact of redistricting--potentially through Gerrymandering or the manipulation of electoral borders to favor a political party--on political polarization in the United States has been found to be minimal in research by leading political scientists. The logic for this minimal effect is twofold: first, gerrymandering is typically accomplished by packing opposition voters into a minority of congressional districts in a region, while distributing the preferred party's voters over a majority of districts by a slimmer majority than otherwise would have existed. The result of this is that the number of competitive congressional districts would be expected to increase, and in competitive districts representatives have to compete with the other party for the median voter, who tends to be more ideologically moderate. Second, political polarization has also occurred in the Senate, which does not experience redistricting because Senators represent fixed geographical units, i.e. states.  The argument that redistricting, through gerrymandering, would contribute to political polarization is based on the idea that new non-competitive districts created would lead to the election of extremist candidates representing the supermajority party, with no accountability to the voice of the minority. One difficulty in testing this hypothesis is to disentangle gerrymandering effects from natural geographical sorting through individuals moving to congressional districts with a similar ideological makeup to their own. Carson et al. (2007), has found that redistricting has contributed to the greater level of polarization in the House of Representatives than in the Senate, however that this effect has been "relatively modest".  Politically motivated redistricting has been associated with the rise in partisanship in the U.S. House of Representatives between 1992 and 1994.
The mass media has grown as an institution over the past half-century. Political scientists argue that this has particularly affected the voting public in the last three decades, as previously less partisan viewers are given more polarized news media choices. The mass media's current, fragmented, high-choice environment has induced a movement of the audience from more even-toned political programming to more antagonistic and one-sided broadcasts and articles. These programs tend to appeal to partisan viewers who watch the polarized programming as a self-confirming source for their ideologies. Countries with less diversified but emerging media markets, such as China and South Korea, have become more polarized due to the diversification of political media. In addition, most search engines and social networks (e.g., Google, Facebook) now utilize computer algorithms as filters, which personalize web content based on a user's search history, location, and previous clicking patterns, creating more polarized access to information. This method of personalizing web content results in filter bubbles, a term coined by digital activist Eli Pariser that refers to the polarized ideological bubbles that are created by computer algorithms filtering out unrelated information and opposing views.
A 2011 study found ideological segregation of online news consumption is lower than the segregation of most offline news consumption and lower than the segregation of face-to-face interactions. This suggests that the filter bubbles effects of online media consumption are exaggerated. Other research also shows that online media does not contribute to the increased polarization of opinions.
A 2017 study found that providing people with impartial, objective information has the potential to reduce political polarization, but the effect of information on polarization is highly sensitive to contextual factors.  Specifically, polarization over government spending was reduced when people were provided with a "Taxpayer Receipt," but not when they were also asked how they wanted the money to be spent. This suggests that subtle factors like the mood and tone of partisan news sources may have a large effect on how the same information is interpreted.
The implications of political polarization "are not entirely clear and may include some benefits as well as detrimental consequences." While its exact effects are disputed, it clearly alters the political process and the political composition of the general public. Solomon Messing and Sean J. Westwood state that individuals do not necessarily become polarized through media because they choose their own exposure, which tends to already align with their views.
United States CongressEdit
Negative effects of polarization on the United States Congress include increased gridlock and partisanship at the cost of quality and quantity of passed legislation. It also incentivizes stall tactics and closed rules, such as filibusters on non-contentious issues and excluding minority party members from committee deliberations. These strategies hamper transparency, oversight, and the government's ability to handle long-term domestic issues, especially those regarding the distribution of benefits. Further, they foster animosity, as majority parties lose bipartisan and legislative coordination trying to expedite legislation to overcome them.
Some scholars claim that political polarization is not so pervasive or destructive in influence, contending that partisan agreement is the historical trend in Congress and still frequent in the modern era, including on bills of political importance. Some studies have found approximately 80% of House bills passed in the modern era to have had support from both parties.
Opinions on polarization's effects on the public are mixed. Some argue that the growing polarization in government has directly contributed to political polarization in the electorate, but this is not unanimous.
Some scholars argue that polarization lowers public interest in politics, party identification and voter turnout. It encourages confrontational dynamics between parties that can lower overall public trust and approval in government., and causes the public to perceive the general political debate as less civil, which can alienate voters. More polarized candidates, especially when voters aren't aware of the increase, also tend to be less representative of the public's wishes.
On the other hand, others assert that elite polarization has galvanized the public's political participation in the United States, citing greater voting and nonvoting participation, engagement and investment in campaigns, and increased positive attitude toward government responsiveness. Polarized parties become more ideologically unified, furthering voter knowledge about their positions and increasing their standard to similarly-aligned voters.
As Mann and Ornstein argue, political polarization and the proliferation of media sources have "reinforce[d] tribal divisions, while enhancing a climate where facts are no longer driving the debate and deliberation, nor are they shared by the larger public." As other scholars have argued, the media often support and provoke the stall and closed rules tactics that disrupt regular policy procedure.
While the media are not immune to general public opinion and reduced polarization allows them to appeal to a larger audience, polarized environments make it easier for the media and interest groups to hold elected officials more accountable for their policy promises and positions, generally healthy for democracy.
Judicial systems can also be affected by the implications of political polarization. For the United States, in particular, polarization lowers confirmation rates of judges; In 2012, the confirmation rate of presidential circuit court appointments was approximately 50% as opposed to the above 90% rate in the late 1970s and early 1980s. More polarized parties have more aggressively block nominees and used tactics to hinder executive agendas. Political scientist Sarah Binder (2000) argues that "senatorial intolerance for the opposing party’s nominees is itself a function of polarization." Negative consequences of this include higher vacancy rates on appellate courts, longer case-processing times and increased caseloads for judges.
Political scientists argue that in highly polarized periods, nominees become less reflective of the moderate voter as "polarization impacts the appointment and ideological tenor of new federal judges." It also influences the politics of senatorial advice and consent, giving partisan presidents the power to appoint judges far to the left or right of center on the federal bench, obstructing the legitimacy of the judicial branch.
Ultimately, the increasing presence of ideology in a judicial system impacts the judiciary's credibility. Polarization can generate strong partisan critiques of federal judges, which can damage the public perception of the justice system and the legitimacy of the courts as nonpartisan legal arbiters.
Political polarization can undercut unified agreement on foreign policy and harm a nation's international standing; divisiveness on foreign affairs strengthens enemies, discourages allies and destabilize a nation's determination.
Political scientists point to two primary implications of polarization with regards to the foreign policy of the United States". First, when the United States conducts relations abroad and appears divided, allies are less likely to trust its promises, enemies are more likely to predict its weaknesses, and uncertainty as to the country's position in world affairs rises. Second, elite opinion has a significant impact on the public's perception and understanding of foreign policy, a field where Americans have less prior knowledge to rely on.
Outside of the U.S., there are plenty of modern day examples of polarization in politics. A bulk of the research into global polarization comes from Europe. One example includes Pasokification in Greece. This is the trend from a shift from the center-left to a more far-left stance. Pasokification was caused by the Greek populous growing dissatisfied with the country's centrist, left wing party and how they handled the Great Recession and the austerity measures the European Union put in place during recovery. Although the shift further to the left was a massive benefits to the liberal population in Greece, the results in Greece (as well as other nations like Germany, Sweden and Italy) have not been able to sustain themselves. Parties who have made the shift left have recently shown a decline in the voting booths, evidence their supporters are uneasy of the future.
The shift in Greece to the far-left is similar to the shift in countries like Poland, France and the U.K. to more far-right conservative positions. In those countries, there is heavy anti-Islam sentiment and the rise of populist commentary. The general population of the right in these countries tends to hold onto these more aggressive stances and pulls the parties further to the right. These stances include populist messages with Islamophobic, isolationist, and anti-LGBTQ language. Much of the polarization in these nations leads to either a more socialist left wing party, or more nationalist right wing party. These more polarized parties grow from the discontent of more moderate parties inability to provide progressive changes in either direction.
There have long been numerous scholarly debates that argue over the concept of political polarization, both in whether it is valid, and how it can accurately be measured. There are four primary arguments against the validity of political polarization: 1) Limitations of the Two-Party System, 2) Issue Partisanship, 3) Cultural Differences, and 4) Westernized Focuses.
Limitations of the two-party systemEdit
By solely acknowledging voting patterns, one cannot make an accurate conclusion as to the presence or absence of political polarization, because in the United States, there is a limited number of presidential candidates in the two-party system. To assume that the majority of voters are mostly or completely in agreement with the plethora of political issues within their party is a false assumption. Despite contrary beliefs, there are many liberal Republicans and conservative Democrats in the U.S. who have differing political beliefs within their parties. However, these voters most often align with their party because of the limited choice of candidates, and to do otherwise (i.e. vote for a third-party candidate) is perceived as a waste of time.
Despite various claims that argue American society is more polarized today than leading up to the U.S. Civil War, numerous scholars explain that much evidence shows there is a relatively stable public opinion on the majority of sociopolitical issues. Where the most polarization exists, rather, is in the "hot topic" or "sensitive" issues (e.g. abortion, gay marriage, U.S. involvement in war). Over-reliance on focusing on opinions regarding social issues to draw conclusion about political polarization is not a valid measurement to fully represent the concept.
In regard to views on public policies, Fiorina and Abrams (2008) found virtually no evidence of an increase in widespread political polarization over the past thirty years. Nonetheless, many scholars explain that it is not an increase in ideological coherence among individuals which separates them; it is the partisan extremism (i.e. Democrat v. Republican) which eventually separates voters into one party or the other.
Proponents of the cultural differences argument are critical of political polarization because of numerous factors, influences, and demographics. Among voter demographic features, there is much evidence of race, sex, age, and educational attainment as being some of the main influences in voting behaviors. In addition to these factors, the geographic region often plays a major role in voting behavior. Lastly, one's socioeconomic status is a reliable predictor of voting behavior. The combination of these factors and influences compel researchers to reconsider the causes of political polarization.
Much like many academic studies, political polarization scholars often are too narrowly focused within one nation and, thus, make broad generalizations regarding the concept from a national study. To have a better picture of the presence or absence of political polarization, scholars must consider widening the scope of their studies to the international contexts.
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