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

Is today’s divide uniquely bad? I’ll pull historical and recent measures to check.

Is political polarization worse than in the past? It depends on what you measure and how far back you look.

Short answer: Yes, by almost every modern measure it is worse than it has been in the last 50-70 years, but not necessarily worse than the most divisive periods in American history, like the Civil War era.

1. By modern measures, polarization is at a 50+ year high

Research focusing on the period since World War II shows a clear increase:

A Pew analysis finds that, on average, Democrats and Republicans are farther apart ideologically today than at any time in the past 50 years. The same conclusion is phrased as on average Democrats and Republicans are farther apart ideologically today than at any time in the past 50 years.

Self-identification has sorted too: conservatives made up 68% of Republicans in 2012 vs 59% in 2000, while liberals were 39% of Democrats vs 27% in 2000.

Researchers 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, with consumers indicating they believe the parties overlap less now than they did in previous years.

Another longitudinal measure: In 1994, only 17% of Republicans and 16% of Democrats reported very unfavorable views of the opposing party. By 2016, those numbers had risen to 58% of Republicans and 55% of Democrats.

Using American National Election Studies (ANES) feeling thermometers, the discrepancy between in-party and out-party scores steadily increased from around 25 degrees in 1978 to around 45 in 2020. Another calculation shows it rising from 22.64 degrees in 1978 to 40.87 degrees in 2016. Almost all the increase has occurred because of increased out-party animus.

Compared internationally, over time, affective polarization — the extent of negative feelings toward those in the other party — has increased more in the US than in any of the other countries studied. One cross-national study found it rose substantially in the United States at 5.6 points per decade, the largest increase among 12 OECD democracies.

Political scientists Keith Poole and Howard Rosenthal's widely used DW-NOMINATE metric, based on roll-call votes, shows that after decades of relatively little polarization, the congressional parties began pulling apart in the mid-1970s. Today they say, "Congress is now more polarized than at any time since the end of Reconstruction".

Other analyses agree: Congress is now more polarized than at any time since the late 1870s Reconstruction Era.

The "middle" has vanished:

> There are now only about two dozen moderate Democrats and Republicans left on Capitol Hill, versus more than 160 in 1971-72.

In 1973-74 there was substantial overlap — 240 House members and 29 senators scored between the most conservative Democrat and most liberal Republican — but by 2011-12 there was no overlap at all in either chamber. Since 2002, when Republican Rep. Constance Morella was defeated and Rep. Benjamin Gilman retired, there's been no overlap at all between the least liberal Democrats and least conservative Republicans in the House. In the Senate, the end of overlap came in 2004.

Both parties have moved away from the center, but Republicans more so, and geographic sorting has reinforced it — nearly half of House Republicans now come from Southern states while nearly half of House Democrats are Black, Hispanic or Asian/Pacific Islander.

2. By longer historical measures, not necessarily the worst ever

When historians extend the comparison to the 19th century, the picture changes:

> for all the hype about the ruptures and partisan rancor in contemporary American society, the strife pales in comparison with much of the nation's past.

> No political issue in 2020 approaches slavery in the mid-19th century in terms of potential divisiveness.

University of Virginia Civil War historian Gary W. Gallagher says that current divisions pale in comparison to those of the mid-19th century.

Other work using NOMINATE data finds that partisan elites in the U.S. are as polarized today as they were around the time of the Civil War — suggesting we have returned to a level last seen then, not exceeded it.

One interpretation often made is: Clearly the country has been more polarized than it is today. What's unusual now is that the political system is more polarized than the country.

The 1960s were also highly polarized — Vietnam, counterculture, black power, women's liberation left the nation polarized — but that polarization was more about social and cultural upheaval and political violence in the streets than about the consistent, one-dimensional left-right sorting we see in Congress today, where voting in Congress is now almost purely one-dimensional — political ideology accounts for about 93 percent of roll call voting choices.

Bottom line

What feels new to many people is not just that elites disagree more, but that dislike of the other side, sorting by geography and media, and lack of ideological overlap in Congress make compromise far harder than it was even in the 1970s-1990s.