The Constitution does not fix the size of the Supreme Court, leaving it to Congress. The Judiciary Act of 1789 set six justices, and Congress changed the number several times: to five in 1801, a change repealed the next year, to seven in 1807, nine in 1837, and ten in 1863. In 1866 Congress reduced the Court to seven, partly to deny President Andrew Johnson appointments, and the Judiciary Act of 1869 restored nine, where the number has stayed since. Several of these changes were tied to the number of federal circuits and to partisan conflict.
On February 5, 1937, President Franklin Roosevelt, frustrated that the Court had struck down New Deal laws, proposed adding one justice for each sitting justice over age 70, up to six, which would have raised the Court to 15. Critics in both parties called it an attack on judicial independence. While the plan was debated, the Court upheld a state minimum wage law in West Coast Hotel v. Parrish on March 29, 1937, a shift often called the switch in time that saved nine, and the Senate shelved the bill in July 1937.
The debate revived after the Senate blocked Merrick Garland's nomination in 2016 and confirmed Amy Coney Barrett shortly before the 2020 election. Some Democrats proposed expanding the Court to 13, and President Joe Biden's commission on the Court reported in December 2021 without recommending expansion. In July 2024 Biden proposed 18-year term limits and a binding ethics code, which Congress did not adopt. Supporters of expansion say it would restore balance after norm-breaking confirmations, while opponents say it would invite retaliation and destroy the Court's legitimacy, and some have proposed an amendment fixing the Court at nine.
| Status | Active |
| Legal basis | Court size set by statute, Judiciary Act of 1869 (28 U.S.C. 1) |
| Official site | supremecourt.gov |
| Size set by | Congress, by statute |
| Original size | Six justices (1789) |
| Largest size | Ten justices (1863) |
| Nine since | 1869 |
| Famous attempt | Franklin Roosevelt (1937), up to 15 justices |
| Recent proposals | 13 justices, 18-year term limits |
| Date | Roosevelt plan February 5, 1937 |