The Supreme Court’s History is Sorely Lacking in Diversity, Presidents and Senates Prefer Nominees Who are Ideologically Like Them, and Other Findings About SCOTUS

The faces of justice have been very lacking in diversity, but it’s starting to improve (sort of)

  • John Roberts (Chief Justice): nominated by George W. Bush, on SCOTUS since 2005
  • Anthony Kennedy: nominated by Reagan, on SCOTUS since 1988
  • Clarence Thomas: nominated by George H.W. Bush, on SCOTUS since 1991
  • Ruth Bader Ginsburg: nominated by Clinton, on SCOTUS since 1993
  • Stephen Breyer: nominated by Clinton, on SCOTUS since 1994
  • Samuel Alito: nominated by George W. Bush, on SCOTUS since 2006
  • Sonia Sotomayor: nominated by Obama, on SCOTUS since 2009
  • Elena Kagan: nominated by Obama, on SCOTUS since 2010

Women are a very new presence on the Supreme Court.

Note: for this chart, “% of justices who are women” refers to people who BECAME justices in the time period specified, so for example the 10% refers to the percentage of women among people who became Supreme Court justices in the 1950–2000 period. This applies to all other charts throughout this post as well.

Red, white, and blue? SCOTUS has really just been white.

Justices come from wealthy backgrounds, although this has been changing.

SCOTUS is very Ivy and actually getting increasingly so.

Age has held steady over time.

Presidents tend to nominate people who hold similar beliefs as them

Correlation between the ideology of presidents and the ideology of people they nominate for SCOTUS. For an interactive version of this chart, see here:

The Senate also tends to confirm nominees who are ideologically similar to them

Qualifications matter little

Party matters little

  • Republican nominees have had slightly more luck than Democratic nominees (79% success rate versus 69% success rate), but the difference is small.
  • Democrat-controlled Senates and Republican-controlled Senates have confirmed nominees at the same rate (77%).
  • Republican-controlled Senates are just as likely (77% likelihood) to confirm Democratic nominees as Republican nominees. Democrat-controlled Senates have actually confirmed Republican nominees at a higher rate (84%) than Democratic nominees (77%) although the difference is minor.
  • Whigs have issues making friends. Whig nominees get confirmed at very low rates (17%), and Whig-controlled Senates confirm nominees — including those from their own party — at very low rates (11% overall). I wonder if not having any friends is one of the reasons they’re no longer around as a political party.
  • Note: Independent nominees look like they have such a high confirmation rate (100%) because there’s only been one Independent nominee in history: Felix Frankfurter, nominated by FDR in 1939 and successfully confirmed.

Ideology matters a lot

Correlation between the ideology of the median Senate member and the ideology of the nominee, for nominees who were successfully confirmed. For an interactive version of this chart, see here:
(Lack of) correlation between the ideology of the median Senate member and the ideology of unsuccessful nominees. For an interactive version of this chart, see here:

Justices’ votes as part of SCOTUS align with their pre-SCOTUS ideology

Correlation between the pre-SCOTUS ideology of the nominee and the percentage of their votes that are liberal after joining SCOTUS. For an interactive version of this chart, see here:

Takeaways, recommendations, learnings

  • Throughout history the Supreme Court’s composition has been very male, very white, very wealthy, and very Ivy League. Most of this is starting to change, with the exception of Ivy League which is accounting for an increasingly higher share of justices’ legal education.
  • Presidents have historically nominated people who share their own beliefs — not only people who have the same party loyalties but who are also close to where they are on the ideological spectrum.
  • Senates have also historically confirmed people who share their own beliefs. Party affinity surprisingly doesn’t seem to matter much, but ideological closeness does. The qualification of the nominee also doesn’t seem to have a big impact on confirmation outcomes.
  • Justices’ voting behaviors tend to align closely with their pre-SCOTUS ideology. Earl Warren was an anomaly.
  • To the Ivy League: you’re educating the vast majority of our past, current, and likely future Supreme Court justices. Please make sure the education you provide is more balanced in perspective than the historical demographics of SCOTUS.
  • Choose your weapon wisely. I did this entire analysis in Excel and Tableau, and did not use SQL this time around. Different tools are good for different things, and you can gain a lot of efficiency by tailoring tool to problem as strategically as possible. I think getting better at that was what allowed me to complete this particular analysis in record time, although I think I could have moved even faster if I used SQL for a few of the questions I was trying to answer.
  • I would benefit from learning more data science and statistics. My recent data projects have involved a lot of correlation analyses, and I think I can extract even deeper insights if I had a better understanding of the statistical nuances underlying the correlations.
  • The quality of the data is incredibly important. For this project, researchers at the University of Washington in St. Louis already did the lion share of the data collection work by bringing together nominees’ demographic information. They also had to consolidate political ideology scores from two different systems (Segal-Cover and DW-NOMINATE) because researchers before them had created and applied different types of scores to different political figures. While having to use two different scoring systems side by side presents its own limitations, I am grateful to have had this pre-consolidated dataset to work from!



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Annie L. Lin

Annie L. Lin

People & ops leader | data storyteller & nerd