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

Short answer: Yes, by most measures—especially in the U.S.—polarization is at or near historic highs, though the full picture is nuanced.

Elite/Congressional polarization

Political scientists tracking congressional voting patterns find striking evidence of a historic shift. Following a period of a much more balanced Congress during the middle of the 20th century, 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. One key metric is the "overlap interval"—how many Republicans sit to the right of the most liberal Democrat (or vice versa). Today, the overlap interval is zero. This was certainly not always true—in the 1960s, you had intervals where about 50 percent of the legislators in the two parties overlapped.

Pew Research's own analysis confirms this: on average, Democrats and Republicans are farther apart ideologically today than at any time in the past 50 years. Notably, there are now only about two dozen moderate Democrats and Republicans left on Capitol Hill, versus more than 160 in 1971-72.

"Affective" polarization (how much people dislike the other side)

This is where the trend is clearest. Affective polarization refers to the political science term for the hostility one person feels towards members of the other party relative to the feelings they have towards members of their own party. Using feeling-thermometer surveys, in 1978 the difference between Americans' ratings of their own party versus the other party was 27 points; that gap had widened to 56 by 2020. More recent data shows the share of Republicans who view Democrats as "very unfavorable" has risen from 17% in 1994 to 62% in 2024, and the mirror image for Democrats is nearly identical.

An important caveat: policy disagreement vs. tribal animosity

Interestingly, researchers note this isn't necessarily because Americans disagree more on actual policy. As one political scientist explains, that doesn't mean politicians are farther apart on policy issues than in the past—what is often missed are changes in the scope of policy issues over time. More broadly, mass polarization in the United States is less about policy-based division and more about people liking their own political camp and disliking the opposing one.

A 2024/2025 Cambridge study reinforces this nuance: polarization almost flatlined during the nineties and noughties before surging, but even now polarization in the US can feel much worse than it is, since political groups have moved further apart in recent years, but these divisions are still fuzzy, and Americans are not split into entirely opposing tribes when it comes to the issues.

Geographic sorting adds to the picture

Americans are increasingly self-segregating geographically by politics: in 1992, 39% of Americans lived in "landslide counties" where one presidential candidate won by 20+ percentage points; by 2024, 57% did.

The historical asterisk

It's worth noting the "worst since the Civil War" framing comes with an important qualifier: some political scientists have pointed out that viewed within the context of data from the last two centuries, today's levels of polarization are not such an alarming anomaly compared to those occurring during the time of slavery and similar points along the historical continuum. In other words, current polarization is extreme by recent historical standards (last 50-150 years), but the U.S. has seen comparably fierce division before—most notably around the Civil War.

Bottom line

By nearly every modern metric—congressional voting patterns, partisan animosity, geographic sorting, and public perception—polarization today is higher than at any point in the last 50+ years, and arguably the highest since the late 19th century. However, it's largely driven by emotional/tribal hostility rather than wider actual policy disagreement, and it's not unprecedented if you go back far enough in American history (e.g., the Civil War era).