Richard J. Leon (born December 3, 1949) is an American jurist who serves as a senior United States district judge of the U.S. District Court for the District of Columbia. He was appointed in 2002 by President George W. Bush and assumed senior status in 2016.

Early life and education Leon was born in South Natick, Massachusetts, on December 3, 1949. His parents were Silvano B. Leon and Rita M. O'Rorke. His paternal grandparents were immigrants from Portugal who settled in Framingham, Massachusetts.

Leon graduated from the College of the Holy Cross with a Bachelor of Arts in psychology in 1971. As an undergraduate at Holy Cross, he was a member of the school's student judicial board, and was a classmate of Clarence Thomas. He then earned his Juris Doctor (J.D.), cum laude, from the Suffolk University Law School in 1974 and earned a Master of Laws (LL.M.) from Harvard Law School in 1981.

Legal career Leon served as a law clerk to the justices of the Massachusetts Superior Court from 1974 to 1975 and to Thomas F. Kelleher of the Rhode Island Supreme Court from 1975 to 1976. Leon was an attorney for the Immigration and Naturalization Service of the United States Department of Justice from 1976 to 1977 and a Special Assistant United States Attorney in the office of the United States Attorney for the Southern District of New York working in the Civil Division from 1977 to 1978.

Leon was an assistant professor of law at St. John's University School of Law from 1979 to 1983 and a senior trial attorney in the United States Department of Justice from 1983 to 1987. Leon served as deputy chief minority counsel on the Select Committee to Investigate Covert Arms Transactions with Iran of the United States House of Representatives, which investigated the Iran-Contra affair, from 1987 to 1988.

Leon was appointed Deputy Assistant Attorney General and served from 1988 to 1989, when he entered private practice in Washington, D.C., first with Baker & Hostetler from 1989 to 1999 and then with Vorys, Sater, Seymour and Pease from 1999 to 2002, when he was appointed to the district court.

Leon was a member of the President's Commission on White House Fellowships from 1990 to 1993. Leon was appointed chief minority counsel on the October Surprise Task Force of the House Foreign Affairs Committee from 1992 to 1993. He served as special counsel to the House Financial Services Committee in 1994. He is an adjunct professor at The George Washington University Law School and the Georgetown University Law Center.

Federal judicial service Leon was nominated to the United States District Court for the District of Columbia by George W. Bush on September 10, 2001, to the seat vacated by Norma Holloway Johnson. Confirmed by the Senate on February 14, 2002, he received his judicial commission five days later. He assumed senior status on December 31, 2016.

WilmerHale v. Executive Office of the President (2025) On May 27, 2025, Judge Leon ruled in WilmerHale v. Executive Office of the President, striking down Executive Order 14250 issued by President Donald J. Trump. The order targeted the law firm WilmerHale due to its association with former Special Counsel Robert S. Mueller III. It directed federal agencies to suspend the firm’s security clearances, restrict access to federal buildings, and review existing contracts. Judge Leon found the order to be retaliatory and unconstitutional, violating the First and Fifth Amendments. In a 73-page opinion, he wrote, “The cornerstone of the American system of justice is an independent judiciary and an independent bar willing to tackle unpopular cases, however daunting.”

Guantanamo Bay Leon was responsible for adjudicating the habeas corpus petitions of several dozen captives held at the Guantanamo Bay detention camp. Boumediene v. Bush, which was eventually considered by the Supreme Court, was first heard by Leon. By August 28, 2008, Leon had 24 cases assigned to him.

The Associated Press reported Leon hoped to resolve those cases before the presidential inauguration in 2009 and was concerned that the public and the detainees will be barred from observing the hearings: "If it can't be done, I have great concern that these hearings will be virtually or exclusively classified, closed to the public and, I might add, to the detainees."

During a hearing on October 23, 2008, Leon commented on the ambiguity of the term "enemy combatant" and criticized Congress and the Supreme Court: "We are here today, much to my dismay, I might add, to deal with a legal question that in my judgment should have been resolved a long time ago. I don't understand, I really don't, how the Supreme Court made the decision it made and left that question open... I don't understand how the Congress could let it go this long without resolving." On November 20, Leon ordered five detainees released from Guantanamo Bay Naval Base due to insufficient evidence.

In December 2008, Leon denied Moath Hamza Ahmed al Alawi's habeas corpus petition, finding the enemy combatant's detention was lawful under the Authorization for Use of Military Force of 2001. In February 2017, Leon denied another habeas corpus petition from al Alawi, rejecting the detainee's claim that the war's hostilities had ceased.

NSA metadata collection unconstitutional On December 16, 2013, Leon ruled that the NSA's bulk collection of Americans' telephone records likely violated the Fourth Amendment to the United States Constitution, though he stayed enforcement of his injunction pending appeal to the D.C. Circuit. Excerpts from his decision are as follows:

Other notable cases