Is polarization worse than ever? I'll gather historical trends to compare today's divisions with the past.
It depends on timeframe and how you define polarization. Research distinguishes:
•Ideological polarization - distance on issues
•Affective polarization - feelings / dislike of the other side
•Elite vs mass polarization - politicians vs general public
Compared to the last 30-50 years: Yes, worse
Most measures show a sharp increase since the 1970s-1990s:
•In Congress, the level of polarization is now the highest since the end of the Civil War. The metric called DW-NOMINATE tracks every roll-call vote in Congress since 1789. It show the current Congress is more polarized than any point since the Reconstruction era.
•Beginning in the mid-1970s, the parties in Congress began to move further apart. One summary found polarization has been steadily getting worse since the early 1970s. Today, we've hit the ceiling on polarization.
•Among the public, the Pew Research Center found Republicans and Democrats are more divided along ideological lines – and partisan antipathy is deeper and more extensive – than at any point in the last two decades.
•The overall share of Americans who express consistently conservative or consistently liberal opinions has doubled over the past two decades from 10% to 21%. As a result, ideological overlap between the two parties has diminished: Today, 92% of Republicans are to the right of the median Democrat, and 94% of Democrats are to the left of the median Republican.
•Partisan animosity has also risen. In each party, the share with a highly negative view of the opposing party has more than doubled since 1994. In 1994 just 17% of Republicans and 16% of Democrats had very unfavorable opinions of the other party. Since then that became 43% of Republicans and 38% of Democrats now view the opposite party in strongly negative terms.
•Researchers at the University of Cambridge tracked shifts across nearly four decades and found divisions were broadly stable through the 1990s and early 2000s, before rising steadily from 2008 onward. Using more than 35,000 responses from the American National Election Studies between 1988 and 2024, they estimate that issue polarization has increased 64%.
•Affective polarization shows a similar trend. A 2019 article in the Annual Review of Political Science, shows that such affective polarization has increased drastically in the last four decades. In comparative work, in the U.S., affective polarization has increased more dramatically since the late 1970s than in the eight other countries they examined.
Political scientists note previous research suggesting that political polarization in the United States is more pronounced now than in the past -- at least among members of the nation's major political parties.
Distribution is uneven
Polarization is not uniform across the population:
•Ideological polarization seems to be largely concentrated among political elites, affective polarization is pervasive among ordinary voters.
•Some scholars argue It is the elites and activists who are polarized, not the public. One Stanford scholar found Despite widespread perceptions of rising political polarization in the United States, the American public is no more polarized than it was before the Reagan era.
•By one measure - variation of responses on an individual issue - research has shown that despite many commentators' concerns about increased polarization in recent decades Americans' attitudes have become no more variable over the past two or three decades.
Some of what looks like polarization is sorting: people with consistent views increasingly align with one party, rather than the whole public moving to extremes. Critics note the Pew study does not offer overwhelming evidence of a sharp increase in polarization but especially in the past few years. Instead, it provides further evidence of party sorting.
Compared to all of American history: No
Even scholars who document record-high modern polarization stress that earlier eras were more divided:
•As a historian who has written and taught about the Civil War era for several decades, I know that current divisions pale in comparison to those of the mid-19th century. Between Lincoln's election and Appomattox the nation literally broke apart, with more than 3 million men taking up arms and 620,000 military deaths.
•Today's social conflicts and partisan strife pale in comparison with much of the nation's past. Recall the racial apartheid that scarred America for a century after the end of slavery, and the urban riots and anti-war protests that inflamed the country during the 1960s.
•No political issue in 2020 approaches slavery in the mid-19th century in terms of potential divisiveness.
In short: by congressional voting records, by ideological consistency, and by mutual dislike, the U.S. is more polarized today than at any point since the 1970s, and more polarized than at any point in the last two decades of Pew polling. But that is still less violent and institution-breaking than the Civil War era, Reconstruction, or the early-to-mid 20th century periods of deep regional and racial cleavage.