Is political polarization worse than it's been in the past?

Short answer: It depends on what you compare and over what time frame — but by several measures, yes, recent decades have seen the highest polarization in modern history, though not necessarily in all of U.S. history.

Congressional/elite polarization is at modern highs

In Congress specifically, the data is fairly unambiguous. A Pew Research Center analysis finds that, on average, Democrats and Republicans are farther apart ideologically today than at any time in the past 50 years. This divergence has left only about two dozen moderate Democrats and Republicans on Capitol Hill, versus more than 160 in 1971-72, as both parties have moved further away from the ideological center since the early 1970s.

Some researchers push the comparison back even further: ideological distance between the parties began to grow during the 1970s to the extent that Congress is now more polarized than at any time since the late 1870s Reconstruction Era.

Affective polarization (dislike of the other side) has also surged

Beyond policy disagreement, Americans' emotional hostility toward the opposing party has grown dramatically. One long-running study found that in 1978, the average American rated members of their own political party 27 points higher than members of the other major party on a 0-100 "feeling thermometer," but by 2016 that gap had grown to 45.9 points.

This trend appears to be uniquely steep in the U.S. compared to peer democracies: political polarization among Americans has grown rapidly in the last 40 years — more than in Canada, the United Kingdom, Australia or Germany. More recent comparative work confirms this: referencing data from 12 OECD countries, researchers argue that the state of U.S. affective polarization is exceptional, with the U.S. having suffered the largest increase in affective polarization over the last 40 years.

The public is also more ideologically sorted

At the voter level, the overall share of Americans expressing consistently conservative or consistently liberal opinions has doubled over the past two decades from 10% to 21%, and 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. A 2025 Cambridge-affiliated study extended this further back, finding that from 1988 to 2024, the US left was 31.5% more socially liberal compared to 1988, while the US right was only 2.8% more conservative — though that same study notes this polarisation may have begun to level off during Biden's term, although it remains far higher than previous decades.

But "worse than ever" overstates it — history had far bloodier divisions

Here's the important caveat: when you zoom out across all of U.S. history, today's polarization is not unprecedented. Historians studying the Civil War era are blunt about this. As one Civil War historian put it: "current divisions pale in comparison to those of the mid-19th century." The scale of violence makes the point starkly — four years of civil war produced at least 620,000 military deaths, the equivalent of roughly 6.5 million dead in 2020 terms, provoked by the institution of slavery, and no political issue in 2020 approaches slavery in the mid-19th century in terms of potential divisiveness.

Other historically rancorous periods include the early republic — the divides following the founding saw Federalists and Anti-Federalists fight so viciously over the Constitution's powers that by 1804, New England Federalists were contemplating secession — and the 1960s-70s, marked by conflicts over Vietnam, race, and women's rights.

Nuance: not all forms of polarization have grown equally

It's also worth noting that polarization isn't monolithic. Some researchers distinguish between polarization and mere "sorting," and one recent study found that income and especially racial groups align into parties, but their ideological distance has not increased over time. Globally, the picture is mixed too: at a global scale, ideological polarization does not appear to have increased among the mass public, in contrast to the trend observed in the United States where growing ideological polarization is now well documented.

Bottom line

So "worse than ever" is probably wrong, but "worse than in living memory, and unusually severe by international standards" is well supported by the evidence.