How Liberal Is Sonia Sotomayor?
The anchor of the Court’s left, measured: every vote since 2009, the tightest bloc on the bench, and the 9 times in five terms she left it — six of them entirely alone.
The most liberal justice on the Court, by nearly every ruler that can be laid against the question — the 7th most liberal career record of the 33 rankable since 1946, the highest same-window share on today’s bench (68.0%), and the furthest from the Court’s center on the scholarly Martin–Quinn score. She is also the most loyal to her bloc of any justice profiled here — 9 breaks in 143 cases, 6.3% — and when she does leave it, she usually goes further left, alone: six of the 9 were solo dissents.
The record, against every justice since 1946
The Supreme Court Database codes each vote liberal or conservative, issue by issue, under definitions explained here. Sotomayor’s career share is 64.6% liberal across 1,091 coded votes since 2009 — 17.4 points above the colleagues who sat on the same cases — ranking her 7th of the 33 justices since 1946 — the highest rank of any sitting justice, one place ahead of Kagan, in a top ten otherwise made of the Warren Court’s liberals. Over the 2020 through 2024 terms her 68.0% edges Jackson’s 67.6% and Kagan’s 65.3% for the highest share on the bench, and the drift series has the gap between her and her colleagues 9.6 points wider now than when she arrived.
The pattern by subject is the mirror of Alito’s: strongest exactly where he is weakest. In civil rights, 75.0% of her votes were liberal against a 48.8% baseline; in criminal procedure, 68.1% against 43.6% — and her dissent rate, 21.9% against 16.0% for her colleagues, is the Court’s second-widest after Jackson’s.
Where she sits on the current Court
Agreement in divided cases, the 2020 through 2024 terms — how often each colleague was on Sotomayor’s side of the judgment when the Court split:
The liberal bloc is the tightest unit on the Court, and she anchors it: 86.4% with Kagan, 86.3% with Jackson — and even her lowest seatmate figure, 83.8% with Breyer, runs higher than the best conservative pairing measured on these pages, Alito-and-Thomas at 79.5%. Then the cliff: the Chief Justice at 45.2%, down to Thomas at 20.9% — the same twenty-point neighborhood, from the other side, that his page reports for her.
When she leaves Kagan and Jackson
Same test as Jackson’s page: a divided case in which both of her seatmates — Kagan and Breyer through 2021, Kagan and Jackson since — voted together and Sotomayor voted the other way. It is the rarest event measured on any of these pages: 9 times in 143 such cases across the 2020 through 2024 terms, 6.3% — against Jackson’s 13.1%, Alito’s 11.8% and Thomas’s 22.4%.
The database codes 6 of the 9 liberal and 3 conservative — but two of the three conservative-coded breaks are its judicial-power conventions at work, not rightward votes: her BP dissent served Baltimore’s climate suit, and her Cameron dissent defended an abortion clinic’s appellate victory. Read by who she landed with, the picture is simpler: six breaks alone — usually further left than her own bloc — and 2 into a conservative-anchored majority.
Alone, and to the left of her own bloc
The solo dissents have a family resemblance: each objects that the Court used — or refused to use — its machinery in a way that closed the courthouse to someone. In Vaello Madero she was the only justice who would have held the SSI exclusion of Puerto Rico residents unconstitutional: “Equal treatment of citizens should not be left to the vagaries of the political process.” In the S.B. 8 docket she alone would have kept the United States’ suit against Texas alive. In Cameron and Berger she alone objected to letting new state officials intervene late to defend an abortion law and a voter-ID law. In Mays she dissented, without opinion, from a summary reversal of habeas relief; in BP, from a reading that gave removal defendants a wider door to appellate review. Kagan and Jackson stayed with the majority in every one.
The rare steps right
Three breaks went the other way, and none reads as ideology. In Brown v. United States she joined Alito’s majority on when a state drug conviction counts under ACCA — across from Jackson, Kagan and Gorsuch. In Feliciano she was the one liberal in the 5–4 majority granting a Coast Guard reservist differential pay. And in Goldman Sachs she endorsed the majority’s legal rules and parted only on disposition — she would have affirmed rather than remand. Set beside Jackson’s five textualist crossings and Thomas’s nine liberal-coded landings, it is the shortest list on these pages: Sotomayor does not really cross; she occasionally reads a statute with the other side.
The Court’s other lone dissenter
Form is where she and Thomas — the two poles of the Court — turn out to share a habit. She has been the lone justice in the minority in 18 career cases, second on the current Court only to his 52, and far ahead of anyone else; six of her 9 bloc breaks were solo. Of her 1,127 recorded votes in the modern file, 247 were dissents — and at the cert stage, her statements respecting denial led the Court in her early terms, nearly all of them criminal cases: the habeas petitioner, the prisoner, the capital defendant the Court declined to hear.
The difference is what the lone dissent is for. Thomas dissents alone to restate a doctrine he believes wrong from the root. Sotomayor’s solos are aimed outward — Vaello Madero reads as an argument to Congress, and her criminal-docket statements as a record of cases the system failed. One justice writes for a future Court; the other, for the people the current one turned away.
The 9 breaks, case by case
Every case from the 2020 through 2024 terms in which both of her seatmates voted together and Sotomayor did not, oldest first.
Solo dissent: the statute lets appeals courts review only the federal-officer and civil-rights removal grounds themselves, and the majority’s reading lets any defendant bootstrap full review by tacking one on.
Concurred in part, dissented in part — she endorsed both of the majority’s legal rules but would have affirmed outright: the Second Circuit had already done what the Court was remanding for. The database seats her beside Gorsuch, Thomas and Alito, whose partial dissent attacked a rule she embraced.
The Court summarily reversed a Sixth Circuit habeas grant; Sotomayor dissented without opinion.
Solo dissent: Kentucky’s attorney general had stipulated himself out of the case and should be held to that choice, not allowed back in after the court of appeals had ruled.
Solo dissent against excluding Puerto Rico residents from SSI: “Equal treatment of citizens should not be left to the vagaries of the political process.”
The S.B. 8 docket: the Court dismissed the United States’ suit against Texas as improvidently granted; Sotomayor alone would have kept the case and vacated the stay.
Solo dissent: North Carolina’s interest was already represented by its attorney general, and the intervention rule does not give a state the right to have multiple parties press the same interest.
Joined Alito’s majority — across from Jackson, Kagan and Gorsuch in dissent — holding a state drug conviction counts under ACCA if the drug schedules matched when the state crime was committed.
Joined Gorsuch’s majority for the reservist; Kagan and Jackson dissented with Thomas and Alito — the same cross-ideological split that puts this case on three of these pages.
Questions
Is Sonia Sotomayor the most liberal Supreme Court justice?
By nearly every ruler, yes. Her career record ranks 7th most liberal of the 33 justices with enough votes to rank since 1946 — the highest rank on the current Court. Over the 2020 through 2024 terms her 68.0% liberal share leads the bench, and the scholarly Martin–Quinn score places her furthest from the Court's center of any justice. The margins over Jackson and Kagan are small; the direction is not in doubt.
How often does Sotomayor vote with Kagan and Jackson?
In divided cases across the 2020 through 2024 terms, with Kagan 86.4% of the time and with Jackson 86.3% — and with Breyer, through his 2022 retirement, 83.8%. No pairing on the conservative side runs that high: the liberal bloc is the tightest unit on the Court, and she anchors it.
Does Sotomayor ever vote with the conservative justices?
Against a united Kagan-and-Jackson (or Kagan-and-Breyer) front, almost never: 9 times in 143 such cases across the 2020 through 2024 terms — 6.3%, the lowest break rate of any justice profiled on these pages. The two that put her in a conservative-anchored majority were Brown v. United States (ACCA drug schedules) and Feliciano (reservist pay).
How often does Sotomayor dissent alone?
More than anyone on the Court except Thomas: 18 career cases as the lone justice in the minority, to his 52. Six of her 9 breaks from a united liberal front were solo dissents — Vaello Madero, Cameron, Berger, the S.B. 8 docket, Mays and BP — and her cert-stage statements, nearly all in criminal cases, led the Court in her early terms.
What is Sonia Sotomayor's judicial philosophy?
At her 2009 confirmation she put it in one sentence: “It is simple: fidelity to the law.” Sixteen terms of votes show where that fidelity presses hardest — the criminal docket, where her 68.1% liberal share runs 24.5 points above her colleagues' on the same cases, and the procedural solos where she objects to the Court deciding — or declining to decide — more than the rules allow.
How this page is made
Every count comes from the Supreme Court Database (Spaeth, Epstein, Nelson, Martin, et al.), justice-centered, 2025 Release 01 (how the voting figures are made). The window is the 2020 through 2024 terms; a “break” is a divided case in which both of her bloc seatmates — Kagan with Breyer through 2021, Kagan with Jackson after — voted together and she did not, the same rule as Jackson’s page. Two coding caveats are flagged above: the database’s judicial-power conventions record her BP and Cameron dissents as conservative votes, and Goldman Sachs seats her beside three conservatives whose partial dissent attacked a rule she joined. Case notes were checked against the slip opinions at supremecourt.gov. Outside figures: solo-dissent counts and Martin–Quinn orderings as reported by Adam Feldman (SCOTUSblog, 2026; Legalytics, 2026); the cert-stage characterization from Robert Yablon’s study in the Yale Law Journal Forum (2014). Quotations: her Vaello Madero dissent; her 2009 confirmation opening statement.