The Economist explains
Is political polarisation in America really rising?
The true degree of separation depends on how you measure it
OVER THE weekend wonks flocked to Seattle for the annual meeting of the American Political Science Association. Among other things, they discussed how political divisions hamper the fight against covid-19. America now lags behind much of the rich world in its vaccine rollout, in part because of the reluctance of some on the right to get jabbed. But the academic debate is not conclusive on the extent to which polarisation is rising; political scientists even disagree on how to define it. How is polarisation measured, and are American voters really growing further apart?
In general, political polarisation is defined as the grouping of people into two extreme positions. The tricky bit is determining which opinions or traits should be used to form those groupings. Polarisation can broadly be categorised two ways, says Lilliana Mason of Johns Hopkins University. The first, “social polarisation”, measures the extent to which a person’s ideology and identity (which includes traits such as race or religion) are associated with their political party. High social polarisation results in increased partisan bias and negative feelings towards supporters of the other party. Nearly 40% of Americans, for example, would be upset if their child married someone who supported a party other than their own. The second category, “issue-position polarisation”, measures the extent to which Americans’ policy preferences reflect extreme positions rather than more moderate ones, irrespective of which party they support.
Depending on which definition you choose, polarisation trends look very different. Social polarisation has increased markedly over the past four decades. Starting after the second world war, and accelerating with the Civil Rights movement, ideological liberals and African Americans shifted towards the Democratic Party while conservatives and white Americans became increasingly Republican, on average (a process known as sorting). Democrats have also become more urban, educated, and female at various points since the 1960s. When a person’s social identity is more tied to their party affiliation, partisan bias grows. In 1978, Americans were 27 points colder toward voters from parties other than their own on a 100-point scale. The gap grew to 56 points by 2020 (see chart, left panel). The same cannot be said for issue-position polarisation over the same period. For instance, about half the population took a moderate stance on abortion in 2016, a proportion that has held steady since 1975. Across issues ranging from the armed forces to government spending, the share of the population holding extreme positions has not trended upwards nearly as much as social polarisation, though it has increased somewhat since 2008 (see chart, right panel).
Political scientists have several hypotheses for why partisan sorting has occurred. One explanation is America’s two-party system, which makes it easier to form strong political identities than in countries with several major parties, where holding views that cross party lines is more common. Another is the growth of media outlets that increasingly appeal to partisan viewpoints. Fox News was started in 1996, and social polarisation accelerated sharply in the years afterwards. Political scientists also point to inequality and the growing population of racial minorities in America, but a consensus has yet to emerge.
So has political polarisation grown in America? In one sense, yes. The link between someone’s social identity, political ideology and party appears to be growing stronger. But in terms of their positions on many issues, Americans have not grown to be as extreme. This has led to a paradox of polarisation. Despite agreeing on much, Americans dislike each other more than ever.
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