The Court from Left to Right
33 justices ranked two ways — by how often they voted liberal, and by how far that put them from the colleagues in the room. The two lists are not the same list.
By raw share of liberal votes it is William O. Douglas at 79.6%, with William Rehnquist last at 29.7%. Measured against the justices who decided the very same cases, the answers change: Thurgood Marshall comes first and the second Justice Harlan comes last. Douglas sat on a liberal Court and Harlan sat on one too — which is exactly why the raw number, on its own, partly ranks the eras rather than the judges.
Two rankings, not one
The first column is the one people mean: the share of a justice’s ideologically coded votes that the Supreme Court Database records as liberal. It is the honest answer to the question as usually asked, and it has a real flaw. The Court chooses its own docket, and that docket changes: a bench hearing criminal-procedure appeals in 1962 and one hearing administrative-law disputes in 2012 will produce different percentages from identical judges.
The second column removes that problem. It is the gap — the justice’s liberal share minus the share for the other justices deciding the same cases. Same docket, same day, same eight colleagues. A positive number means voting liberal more often than the people in the room; a negative one, less often. Zero is not neutrality. It is agreement with the bench of the day.
Neither is the truth on its own. Read them together, and where they disagree, believe the second one about the justice and the first one about the era.
All 33, Most to Least Liberal
Ordered by raw liberal share. The last column is the rank by gap instead, with the arrow showing how far a justice moves between the two orderings.
| # | Justice | Liberal votes | Vs. own bench | Gap # |
|---|---|---|---|---|
| 1 | Douglas OT1946–1975 | 79.6% | +22.3 | 2↓1 |
| 2 | Warren OT1953–1968 | 74.9% | +12.7 | 9↓7 |
| 3 | Black OT1946–1970 | 73.4% | +14.6 | 6↓3 |
| 4 | Fortas OT1965–1968 | 72.6% | +9.3 | 12↓8 |
| 5 | Marshall OT1967–1990 | 72.4% | +23.9 | 1↑4 |
| 6 | Brennan OT1956–1989 | 71.5% | +18.5 | 3↑3 |
| 7 | Sotomayor OT2009–2024 | 64.7% | +17.3 | 4↑3 |
| 8 | Kagan OT2009–2024 | 62.1% | +14.5 | 7↑1 |
| 9 | Stevens OT1975–2009 | 60.5% | +14.2 | 8↑1 |
| 10 | Ginsburg OT1993–2019 | 60.4% | +14.9 | 5↑5 |
| 11 | Breyer OT1994–2021 | 57.1% | +11.3 | 11 |
| 12 | Souter OT1990–2008 | 57.1% | +11.4 | 10↑2 |
| 13 | Clark OT1949–1966 | 54.0% | −7.6 | 17↓4 |
| 14 | Blackmun OT1969–1993 | 51.7% | +2.5 | 13↑1 |
| 15 | Stewart OT1958–1980 | 50.7% | −6.7 | 15 |
| 16 | White OT1961–1992 | 48.8% | −5.1 | 14↑2 |
| 17 | Frankfurter OT1946–1961 | 46.5% | −11.9 | 24↓7 |
| 18 | Minton OT1949–1956 | 46.0% | −8.6 | 19↓1 |
| 19 | Reed OT1946–1956 | 45.5% | −11.5 | 23↓4 |
| 20 | Vinson OT1946–1952 | 45.2% | −9.0 | 20 |
| 21 | Burton OT1946–1958 | 44.8% | −13.1 | 25↓4 |
| 22 | Whittaker OT1956–1961 | 43.6% | −19.1 | 31↓9 |
| 23 | Harlan OT1954–1970 | 43.1% | −22.0 | 33↓10 |
| 24 | Kennedy OT1987–2017 | 41.7% | −7.1 | 16↑8 |
| 25 | Roberts OT2005–2024 | 41.7% | −7.8 | 18↑7 |
| 26 | R. Jackson OT1946–1953 | 39.8% | −14.5 | 26 |
| 27 | Powell OT1971–1986 | 39.3% | −10.3 | 22↑5 |
| 28 | O'Connor OT1981–2005 | 38.4% | −10.2 | 21↑7 |
| 29 | Scalia OT1986–2015 | 35.0% | −14.6 | 27↑2 |
| 30 | Burger OT1969–1985 | 34.0% | −17.0 | 29↑1 |
| 31 | Alito OT2005–2024 | 33.9% | −16.9 | 28↑3 |
| 32 | Thomas OT1991–2024 | 32.0% | −17.4 | 30↑2 |
| 33 | Rehnquist OT1971–2004 | 29.7% | −20.6 | 32↑1 |
7 more justices appear in the database with records too short to rank — Barrett, Goldberg, Gorsuch, K. Jackson, Kavanaugh, Murphy, Rutledge.
Where the two lists disagree
Four justices move far enough between the orderings that the choice of measure changes what you would say about them.
The largest disagreement on the page. A 43.1% liberal share puts Harlan in the middle of the pack; measured against the justices who sat with him he is the single most conservative record in the database, 22.0 points below his own bench. He spent his career dissenting from the Warren Court, and a raw percentage cannot see that — because the Warren Court decided liberal cases liberally, and Harlan was in the room for all of them.
Nearly the same story and rarely told: 43.6% raw, 19.1 points below the Court he sat on, which moves him from 22nd to 31st. His tenure was short and unhappy, and the raw figure flatters it.
The cleanest illustration of why one number is not enough. Clark voted liberal in 54.0% of coded cases — above the halfway mark, and 13th of 33. Against the justices deciding the same cases he is 7.6 points to the conservative side. Both numbers are correct. Only the second tells you where he sat on his own Court.
The reverse case. Kennedy’s 41.7% is one of the lower raw shares here, which reads as firmly conservative; against his own colleagues he is 7.1 points under, and rises eight places to 16th. He was the swing vote of a conservative Court, and only the relative measure shows it.
The Other Order
The same 33 justices ranked only by distance from their own bench — the five furthest to each side.
Method, and its limits
Built from the Supreme Court Database (2025 Release 01, justice-centered), covering the 1946 through 2024 terms. One vote per justice per case. Cases the database declines to code ideologically, and cases where it records a justice on both sides, are excluded. A justice needs 500 coded cases to be ranked at all, which is why 7 of the 40 covered here do not appear in the table.
“Liberal” is the database’s word, not ours, and it is a term of art rather than a political score: pro-union in labor cases, anti-business in economic cases, pro-federal-power in federalism cases, and — in the database’s own deliberate usage — pro-United-States in tax cases. Criminal procedure, civil rights, the First Amendment, due process, privacy and attorneys share a single combined definition running to seventeen clauses, so the label carries less precision in those areas than a ranking implies. The full definitions are on the codebook page.
A ranking is a stronger claim than the data supports at the margins. Adjacent places are often separated by a fraction of a point — Kennedy and Roberts both round to 41.7%, and Souter and Breyer both to 57.1%. Where the published figures tie, the ranking is settled on the exact unrounded rate (Kennedy 41.7012 to Roberts 41.6914; Breyer 57.1293 to Souter 57.0909), which is precise but not meaningful. Treat the ends as real and the middle as a cluster.
The broader objection to all vote-derived ideology scores comes from Michael Bailey: they are partly circular, since votes are used to build a measure of ideology which is then used to explain votes, and apparent differences can come from changes in which cases reached the Court. Both columns here inherit that limit. The gap column narrows it, because the comparison group heard the identical docket, but it does not remove it.
Questions
Who is the most liberal Supreme Court justice?
It depends which question you are asking. By raw share of liberal votes, William O. Douglas — 79.6% across nearly 3,600 ideologically coded cases from 1946 to 1975. Measured instead against the justices who decided the same cases, Thurgood Marshall comes first, 23.9 points more liberal than his own colleagues. Douglas sat on a more liberal Court than Marshall did, and a raw percentage cannot tell the two apart.
Who is the most conservative Supreme Court justice?
By raw share, William Rehnquist, at 29.7%. Against his own colleagues, the second Justice Harlan — 22.0 points to the conservative side of the Warren Court he served on, the widest conservative gap in the database. (The widest gap in either direction belongs to Thurgood Marshall, 23.9 points the other way.) Rehnquist sat with conservatives; Harlan largely did not.
Does a low liberal-vote share mean a justice was conservative?
Not on its own. The share depends heavily on which cases the Court chose to hear, and those change decade by decade. Anthony Kennedy and John Roberts both record low raw shares while sitting close to the centre of their own benches; Tom Clark records a share above 50% while sitting to the right of his. That is why both measures appear side by side here.
What does the Supreme Court Database mean by a "liberal" vote?
It is a term of art defined issue by issue, not a political label — pro-union in labor cases, anti-business in economic cases, pro-federal-power in federalism cases, and pro-United-States in tax disputes. Criminal procedure, civil rights, the First Amendment, due process, privacy and attorneys all share a single combined definition. The coding is Harold Spaeth’s and his successors’, and scholars contest parts of it.
Companion pages: how far each justice moved across a career, and who voted with whom.