I read about asymmetrical polarization in the federal government. It said that Republicans became more conservative more than Democrats became more liberal in Congress. I have found that the opposite may be the case in the general public.

I also saw an article about how, since 2000, the parties' coalitions have shifted in terms of ideology. This shift mostly affected the Democrats, partly because Republicans were already predominantly conservative. Exhibit A:

In 2000, 28% of Democrats said I'm a liberal in an ongoing Gallup poll. In 2018, that number increased by 23 percentage points to 51%. For comparison, Republican conservative identification was up 12 points. Exhibit B:

Polarization by party, 2015 and 2017

Can you see that the Republican one stayed flat in 2015-2017 but the Democrat one moved significantly to the left. This appears to be a relatively recent phonomenon. This measures ideology based on questions and not self identification. There is a trace from 2011 to 2015. The gap only really grew after about 2004.

Are Democratic supporters and voters more ideologically polarized than their counterparts?

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    The data here seems clear enough, so what's the question? Also please edit with links to sources of the images. Is there a Republican version of the first chart to compare with?
    – Brian Z
    Commented Jul 31, 2020 at 13:57
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    This article provides additional data you may want to reference: pewresearch.org/politics/2014/06/12/…
    – minsalty
    Commented Jul 31, 2020 at 14:18
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    Not really. This is because Democrats shifted a lot from 2015-2017 while Republicans remained constant. I want to savor the maximum.
    – user33357
    Commented Jul 31, 2020 at 14:43
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    I'm going to point out that this chart is deeply misleading because of the time-frame chosen (I assume this is deliberate). If we were to extend the timeframe back to the 1990s, we would see a steep rightward shift in the GOP, something that had completely crystalized by the middle of Obama's tenure. This chart begins after that radicalization of the Right, and argumentatively wonders whether the Left is disproportionately radicalized. It's like someone who waits until the car has driven 10 feet into a field, and then complains when the driver jerks the wheel back towards the road. Commented Jul 31, 2020 at 14:45
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    @TedWrigley I'd think an answer refuting the claims would be better than closing. The question is, "This is what I found, is it true?" You're claiming it's not true and concluding therefore it should be closed?
    – Just Me
    Commented Jul 31, 2020 at 17:09

2 Answers 2


Absolutely not. Whether intentional on your part or not, the use of 1994 as the cutoff is a calculated move by the graph-maker, as 1990-1994 was an unprecedented surge in Republican conservatism before Newt Gingrich got the party back on-message with his Contract with America. If we show the whole line in multiple aspects, it shows the real story:

WWI forced the parties closer together, the New Deal pushed them apart again, WWII made both parties more collectivist, and Vietnam/the Southern Strategy emboldened the Republicans to adopt an unprecedented level of conservatism and to a much smaller degree, saw the Democrats move back to their baseline.

However, on social issues, the parties are nearly in sync in a way not seen since WWII. We agree that black people and gay people are actually people, and that their lives matter. We realize that poverty is not a moral failure. We realize that the War on Drugs was a disaster with very few positives and a whole lot of negatives. And we are closer than we've ever been to universal healthcare.

House Liberal/Conservative Polarization 1879-2015 Senate Social Policy Polarization 1879-2014

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    The Republican party is now leaning towards universal healthcare?
    – Jontia
    Commented Jul 31, 2020 at 19:24
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    @Jonita: Citizens who identify as Republican are actually quite sympathetic to universal healthcare, in one form or another. But the Republican party leadership and policy planners have taken a strong anti-healthcare stance for reasons of their own. This is why they consistently use the repeal and replace slogan: repeal is the party goal; replace is a sop to the large number of their constituents who favor healthcare. Notice how the GOP has never offered a serious replacement for Obamacare, even while they frequently aver they have one in the works. Commented Jul 31, 2020 at 19:39
  • Needs an explanation of the numbers on the Y axes.
    – dan04
    Commented Jul 31, 2020 at 23:46
  • @Jontia Moreso than they have in the last 50 years.
    – Carduus
    Commented Aug 1, 2020 at 13:42

As this answer neatly addresses the fact that historically the parties have been more polarized, I'd like to address the extent to which they are asymmetrically polarized now.

Yes, there is polarization. People who identify with different political parties do not agree on political ideas. But is there asymmetrical polarization? I don't think the data we have backs this claim up. In regards to exhibit A, the graph does not tell us much about any overall asymmetric political polarity between the parties. Since you included the Democratic graph, I'll include the Republican graph found here.

enter image description here

In 2017, there was a 64% difference between conservative and liberal identifying Republicans. Compare this to the graph of the Democrats you provided, where the internal party difference between conservatives and liberals, 38%, is growing more quickly than in the Republican party. However, the Republican party is already very polarized internally, so the Democratic party might just be catching up. And we can't directly apply these percentages to the graph of all American's ideological views, as that graph splits people into liberal, conservative, and independent, not Democrats or Republicans. So we are not able to address the asymmetric polarity of the US overall.

Now for exhibit B. I I believe these figures are from here, but I will be referencing the full report.

We know that overall, the ideological consistency of Americans is shifting left. The report includes this figure:

enter image description here

and provides the following explanation:

At the same time, the center of the scale has shifted in a somewhat liberal direction over time. To a large extent, this is the result of the public’s growing acceptance of homosexuality and more positive views of immigrants, shifts that are seen among both Democrats and Republicans (GOP attitudes about immigrants are little changed over the last decade, but Republicans are substantially less likely to view immigrants as a burden on the country than they were in the 1990s).

This is interesting, but it doesn't necessarily address why the median in the graphs you provide shifts left for the Democrats and does not shift either way for the Republicans. The issue is that there isn't one explanation for this. The shift left in the Democratic median could be because of increasing internal liberal consistency with the big ticket items, like homosexuality and immigration, but these are also increasing in the Republican party. The shift left could also be in part due to other more polarizing issues. The Republican median may not shift because of opposing effects in the change of views within the party. For example, more support for homosexuality, less support for environmental policies.

But to be clear, from these graphs and the analysis in the report, we don't know that there is asymmetric polarization. Nor do the authors apparently, as they avoid making any claim about asymmetry. What we do know is that there is more political polarization recently. And while there is evidence that since 2017 the number of Democrats identifying as liberal is increasing, this is not clearly causing asymmetric polarization.

  • And if we wanted to actually get to a science-level answer, we'd need to answer the question of how we're defining the center line of neutrality.
    – Carduus
    Commented Aug 1, 2020 at 14:03