Sidney Runyan Thomas

Sidney Runyan Thomas (born August 14, 1953) is a senior United States circuit judge on the Ninth Circuit Court of Appeals. Appointed by President Bill Clinton in 1996, he served as an active‑service judge for more than two decades, including a term as chief judge from 2014 to 2021, before assuming senior status in May 2023. He continues to sit on panels and his chambers are located in Billings, Montana.

Early life and legal career

Thomas was born in Bozeman, Montana, and pursued higher education within the state. He earned a Bachelor of Arts degree from Montana State University in 1975. Continuing his studies at the University of Montana School of Law, he received a Juris Doctor with honors in 1978. While an undergraduate, Thomas was appointed as a student member of the state Board of Regents of Higher Education in 1974 and was reappointed to that body in 1976, reflecting early involvement in public service.

Following admission to the bar, Thomas entered private practice at the Billings firm Moulton, Bellingham, Longo & Mather. Over the course of his career there he rose to senior partner status and focused on a range of complex matters, including commercial litigation, government-related disputes, bankruptcy proceedings, and media law issues. In addition to his practice, Thomas served as the standing bankruptcy trustee for all cases filed in the Billings Division of the United States District Court for the District of Montana from 1978 through 1981, overseeing the administration of numerous insolvency matters.

Thomas also contributed to legal education. From 1982 until 1995 he was an adjunct instructor at Rocky Mountain College, where he taught law courses and mentored students preparing for legal careers. His combined experience in private practice, bankruptcy administration, and academia provided a broad foundation for his later judicial work.

Federal appellate service

President Bill Clinton nominated Thomas to the United States Court of Appeals for the Ninth Circuit on July 19 1995, filling the vacancy created by Judge Dorothy Wright Nelson. The nomination experienced a brief procedural delay after Senator Conrad Burns of Montana sought to postpone Thomas’s confirmation pending consideration of legislation that would split the Ninth Circuit into two separate circuits. The Senate ultimately confirmed Thomas by voice vote on January 2 1996, and he received his commission two days later.

During his tenure as an active judge, Thomas handled a wide array of appellate matters arising from the expansive jurisdiction of the Ninth Circuit, which includes states such as California, Arizona, Nevada, Oregon, Washington, Idaho, Alaska, Hawaii, and territories in the Pacific. He was appointed chief judge on December 1 2014, a role he fulfilled until December 1 2021. As chief judge, Thomas oversaw administrative functions of the circuit, managed case assignments, and represented the court in its interactions with other branches of government.

In addition to his judicial duties, Thomas served as the en banc coordinator for the Ninth Circuit. In that capacity he performed procedural responsibilities akin to those of a parliamentarian, influencing how cases were considered by the full bench. Colleagues have noted his consistent application of procedural rules and the stability of his rulings in that role.

On March 29 2022 Thomas announced his intention to assume senior status once a successor was confirmed. He formally took senior status on May 4 2023, at which point he retained the ability to hear cases on a reduced basis while continuing to contribute to the court’s workload from his Billings chambers.

Thomas’s judicial service has also intersected with consideration for higher office. Senior officials in the White House listed him among roughly ten candidates evaluated as potential nominees to replace retiring Supreme Court Justice John Paul Stevens. In April 2010, both President Barack Obama and Vice President Joe Biden conducted separate interviews with Thomas at the White House as part of that selection process; ultimately, Solicitor General Elena Kagan was nominated and confirmed.

Jurisprudence and legacy

Throughout his appellate career, Judge Thomas authored opinions on a variety of substantive issues. In 2006 he wrote for the court in *Nadarajah v. Gonzales*, a civil‑rights case involving an immigrant with alleged ties to the Tamil Tigers; the decision addressed procedural and constitutional questions surrounding immigration enforcement.

Thomas participated in the majority opinion in *Peruta v. San Diego* (2016), a case that examined the constitutionality of San Diego’s restrictive gun‑ownership ordinance. The panel upheld the city’s policy, interpreting Second Amendment considerations within the context of local regulation.

On June 26 2020 Thomas authored an opinion granting summary judgment to the Sierra Club, holding that the Department of Defense’s allocation of $2.5 billion toward construction of a border wall violated the Appropriations Clause of the Constitution. The Ninth Circuit’s decision was subsequently reversed by the United States Supreme Court on July 31 2020 in a closely divided 5‑4 ruling.

In May 2021 Thomas issued an opinion clarifying that a child who entered the United States as a minor does not need to possess lawful permanent residency in order to derive citizenship automatically when a parent naturalizes. The decision contributed to evolving jurisprudence on derivative citizenship and the rights of undocumented youth.

Beyond specific rulings, Thomas’s long service on the Ninth Circuit has been marked by his procedural stewardship as en banc coordinator and his leadership during a period of significant caseload growth for the nation’s largest appellate jurisdiction. His background in commercial litigation, bankruptcy, and media law informed a pragmatic approach to complex legal questions, while his teaching experience contributed to mentorship of younger attorneys and clerks.

Thomas remains active on the bench as a senior judge, continuing to hear cases and contribute to the development of federal law within the Ninth Circuit’s diverse jurisdiction. His career reflects a trajectory from Montana‑based private practice and academic instruction to prominent roles in one of the nation’s most influential appellate courts. Married to Martha Sheehy, an attorney practicing in Billings since 1988, Thomas maintains personal ties to his home state while serving at the federal level.

Overall, Sidney Runyan Thomas’s judicial record exemplifies a blend of substantive legal analysis and procedural expertise, shaping precedent across areas ranging from civil rights and immigration to environmental law and constitutional interpretation. His tenure as chief judge and ongoing senior service underscore a sustained commitment to the administration of justice within the United States federal judiciary.