There are various causes of political polarization and these include political parties,
redistricting, the public's
political ideology, the mass media, and political context.
Party polarization 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 2010s 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. In this sense, political polarization could be 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. 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". Other theories state that 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 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
multi-party systems,
Giovanni Sartori 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 multi-party 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 multi-party 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. Following
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, say 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.
The public 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 claim that political polarization is a natural and regular phenomenon. Party loyalism is a strong element of voters' thinking. Individuals who have higher political knowledge will not be influenced by anything a politician says. The polarization is merely a reflection of the party that the voter belongs to, and whichever direction it moves in. 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. Fernbach, Rogers, Fox and Sloman argue that it is a result of people having an exaggerated faith in their understanding of complex issues. Asking people to explain their policy preferences in detail typically resulted in more moderate views. Simply asking them to list the reasons for their preferences did not result in any such moderation. Studies undertaken in the U.S. (2019) and the UK (2022) have found that political polarization is generally less acute among the public than is portrayed in the media. Moreover, non-nuanced reporting by the media about poll data and public opinions can even aggravate political polarization.
Morris Fiorina 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. Fiorina connects this phenomenon to what he describes as "party sorting", which is where political ideologies tend to associate with specific political parties (conservatives with the Republican Party and liberals with the Democratic party). 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., 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 were no longer supportive of
apartheid, and, therefore, no longer ideologically aligned with their party.
Afrikaners, white English-speakers, and
Indigenous 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 Party of Germany, 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.
The media Also stated by Sheena Peckham, algorithms used by social media to operate creates an echo-chamber for the user causing selective exposure and thus leading to online hate, misinformation, malinformation and more (Peckham, 2023). A number of techniques were employed by the researchers and social scientist to trace the relationship between internet usage. Lelkes, along with his colleagues, use state right-of-way laws, which affect the cost of internet infrastructure, as an instrument used for internet access in their country, and discovered a positive relation between internet access and affective polarization in the country. At the same time, another experiment was conducted in which individuals in the US. were asked to deactivate their Facebook account for a $102 incentive, prior to the US. midterm election. It was found that those who deactivated their accounts and did not use Facebook were less polarized as compared to those individuals whose accounts were still activated during the experiment. In addition, Boxell assess ANEX data from 1972–2016 by age cohorts analyzing their likelihood of using social media. The study found that the largest polarization index occurred among the oldest cohort, which was less likely to use social media (Boxell et al., 2017). Thus, he found a small or negative relation between internet usage and polarization. Also, Markus Prior in his article tried to trace the causal link between social media and affective polarization but he found no evidence that partisan media are making ordinary American voters more partisan, thus negating the role of partisan media as a cause of affective polarization (Prior, 2013). 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.
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. For instance, in an experiment where people could choose the content they wanted, people did not start to dislike their political opponents more after selecting between pro- or anti-immigration content; however, people started to counterargue the content. 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. This is confirmed by another study that shows that different emotions of messages can lead to polarization or convergence: joy is prevalent in emotional polarization, while sadness and fear play significant roles in emotional convergence. These findings can help to design more socially responsible algorithms by starting to focus on the emotional content of algorithmic recommendations. Research has primarily focused on the United States, a country with high polarization that has also increased over time. In Sweden, there is a stable ideological polarization over time. Experiments and surveys from Sweden also give limited support to the idea of increased ideological or affective polarization due to media use.
Political context Some 2020s studies emphasize the role of electoral context and the way parties interact with each other. For example, a 2023 study shows that coalition partnership can moderate the extent of affective polarization over parties;
Ranked-choice voting has also been put forward as a solution to political polarization. When politicians repeatedly favor partisan media outlets, they reinforce their supporters' existing biases, which can further fuel political polarization within the public. ==Consequences==