Supreme Court recusal is governed by 28 U.S.C. § 455, which requires a justice to step aside from any case where their impartiality could reasonably be questioned or where specific conflicts apply. The decision rests with each justice individually. No colleague can vote them off a case, and no substitute is brought in to take their seat. When a justice recuses, the remaining members decide the case with whatever number is left.
When a Justice Must Step Aside
Section 455 works in two layers. Subsection (a) is the broad standard: a justice must withdraw from any proceeding where a reasonable, well-informed person would doubt their neutrality. Proof of actual bias is not required. If the situation looks bad enough to raise legitimate questions, the justice is supposed to step aside.
Subsection (b) lists specific triggers that require recusal regardless of how things look:1Office of the Law Revision Counsel. United States Code Title 28 Section 455
- Personal bias against a party, or firsthand knowledge of disputed facts in the case.
- Prior work on the same matter as a lawyer in private practice, including work done by a former law partner during the partnership, or service as a material witness.
- Prior government service in which the justice participated as counsel, adviser, or witness, or expressed an opinion on the merits.
- A financial interest held by the justice, their spouse, or a minor child in their household. Any ownership stake counts, no matter how small, and serving as a director or active participant in a party’s affairs also qualifies.
- A relative within the third degree of relationship (parents, children, siblings, grandparents, aunts, uncles, and their equivalents on the spouse’s side) who is a party, an officer or trustee of a party, a lawyer in the case, or a likely material witness.
Stock ownership is the most common reason justices step aside. In a single term the Court may log well over a hundred recusals driven by financial holdings. There is one important carve-out: owning shares in a mutual fund or common investment fund that happens to hold stock in a party does not count as a financial interest in that company, provided the justice does not help manage the fund. Individual stock holdings get no such pass. A single share in a company that is a party to a case triggers mandatory recusal.
A separate statute, 28 U.S.C. § 144, lets a party file an affidavit alleging personal bias, but by its own terms it reaches only district court proceedings and does not apply to the Supreme Court.2Office of the Law Revision Counsel. United States Code Title 28 Section 144
When Parties Can Waive a Conflict
Section 455(e) draws a hard line between the two tiers. If the only ground for recusal is the general appearance-of-impartiality standard in subsection (a), the parties can waive it, but only after the justice fully discloses the basis for the potential conflict on the record. If the ground falls under one of the specific triggers in subsection (b), no waiver is allowed. Parties cannot consent to a justice hearing a case in which that justice holds stock in a party or has a close relative involved.1Office of the Law Revision Counsel. United States Code Title 28 Section 455
The 2023 Code of Conduct and the Duty to Sit
For decades, lower federal judges operated under a formal ethics code while the justices did not. That changed in November 2023, when the Court adopted its own Code of Conduct for Justices of the Supreme Court of the United States.3Supreme Court of the United States. Code of Conduct for Justices of the Supreme Court of the United States The justices described the code as largely a codification of principles they had already followed, issued to dispel the perception that they considered themselves exempt from ethics rules.
Canon 2 requires justices to avoid impropriety and the appearance of impropriety. Canon 3B addresses recusal directly and states that “A Justice is presumed impartial and has an obligation to sit unless disqualified.” That phrasing reflects the duty-to-sit doctrine: stepping aside when not legally required carries its own cost, because it can leave the Court unable to resolve a legal question.
The commentary also recognizes the “rule of necessity,” citing United States v. Will (1980) for the proposition that § 455 does not override it. Under this rule, a justice may participate in a case despite a potential conflict if the Court would otherwise be unable to function because too many members are disqualified. Critics have argued that neither the duty to sit nor the rule of necessity should operate as exceptions to the statutory grounds, but the Court’s code now treats both as part of its recusal framework.
Who Decides Whether a Justice Recuses
Supreme Court recusal is almost entirely self-policed. Each justice individually decides whether to participate, and no formal mechanism allows the other eight to disqualify a colleague. The statement accompanying the 2023 code confirmed the long-standing practice: “Individual Justices, rather than the Court, decide recusal issues.”3Supreme Court of the United States. Code of Conduct for Justices of the Supreme Court of the United States
When a justice does step aside, the recusal appears in the Court’s orders list or published opinion as a short note that the justice took no part in the consideration or decision of the case. No explanation is required. A few justices have issued written statements explaining their reasoning, but that remains the exception.
Parties can file a motion asking a particular justice to recuse. The Court’s established practice is to refer the motion to the challenged justice, who decides unilaterally. If the justice declines, there is no appeal within the Court. This differs sharply from some state supreme courts, which require a challenged justice to either step aside or refer the question to the remaining members for a collective ruling. In practice, Supreme Court recusal motions rarely force a withdrawal that the justice was not already inclined to make. The only outside checks are public criticism and, in theory, congressional impeachment.
Conflict screening is systematic. The Court relies on disclosure statements that parties file under its rules, and in February 2026 it adopted new rules requiring filings to include comprehensive lists of litigants along with stock ticker symbols, with automated software cross-checking those lists against each chambers’ conflict information.
What Happens to a Case When a Justice Steps Aside
Unlike lower appellate courts, the Supreme Court does not bring in a substitute. A recused justice simply does not participate, and the remaining justices decide the case. That has consequences at every stage.
Granting Review
The Court grants certiorari under the Rule of Four: at least four justices must vote to hear a case.4United States Courts. Supreme Court Procedures A recusal does not lower that number. Four votes are still required even when only eight justices are participating, which effectively raises the proportional threshold.
Ties on the Merits
If a recusal leaves an even number of justices and they split evenly, the lower court’s ruling stands. The Court describes this as “affirmed by an equally divided Court.” The result resolves the particular dispute but creates no precedent, leaving the underlying legal question unsettled for future cases.
Quorum Problems
Federal law requires at least six justices for a quorum.5Office of the Law Revision Counsel. United States Code Title 28 Section 1 If recusals drop the Court below six qualified members, 28 U.S.C. § 2109 provides two fallbacks. For cases that reached the Court by direct appeal from a district court, the Chief Justice can transfer the matter to the relevant federal appeals court for a final decision. For other cases, if a majority of the qualified justices believe the matter cannot be resolved at the next term either, the Court affirms the lower court’s judgment with the same effect as an equally divided ruling.6Office of the Law Revision Counsel. United States Code Title 28 Section 2109 Such situations are rare but not theoretical, especially in cases involving the federal government where multiple justices may have served in relevant roles before joining the bench.
Whether Congress Can Enforce More
Whether Congress can impose enforceable recusal standards on the Supreme Court remains an open constitutional question. Congress already sets the number of justices, controls the Court’s budget, and holds the impeachment power. Several bills in recent sessions have proposed extending the formal judicial conduct system to the justices or creating an external enforcement mechanism.7Congress.gov. Congressional Control over the Supreme Court Article III establishes “one supreme Court” at the top of the federal judiciary, and letting lower court judges review ethical decisions by justices would arguably conflict with that structure. Proponents of legislation respond that requiring compliance with an ethics code is a permissible exercise of legislative authority rather than an intrusion on judicial independence. The Court’s adoption of its own code in 2023 may have eased some of the legislative pressure, but the question of who enforces the rules when a justice disagrees with outside expectations has not been resolved.