While at law school, Mr. Days worked for a civil rights lawyer in Georgia and afterward briefly joined a small firm in Chicago. He and his wife then served in the Peace Corps for two years in Honduras.
Mr. Days came to the attention of President Carter when Mr. Carter appointed Griffin B. Bell as attorney general. Judge Bell, who had sat on the U.S. Court of Appeals for the Fifth Circuit, had been impressed with Mr. Days when the young lawyer was arguing school desegregation cases in the South. Mr. Days headed the civil rights division for the duration of the Carter administration.
During his later stint as solicitor general, Mr. Days argued 17 cases before the Supreme Court and oversaw a group of lawyers who made more than 180 appearances.
One of his most noted cases was his successful argument against term limits for members of Congress. The 1995 decision, U.S. Term Limits v. Thornton, threw cold water on a popular movement, heralded by Newt Gingrich, the speaker of the House, in his Contract With America, that had nominal support from many politicians, but little real enthusiasm.
After serving as solicitor general, Mr. Days returned to Yale, where he hung a sign in his office saying, “No soliciting.” He continued to teach while practicing at a private firm, Morrison Foerster, in Washington. He led the firm’s Supreme Court and appellate group from 1997 until his retirement in 2011. He retired from Yale in 2017.
In addition to his wife, he is survived by two daughters, Dr. Alison L. Days and Elizabeth J. Days; two granddaughters; and his sister, Jacquelyn D. Serwer.
Reflecting on his life in an interview with his daughter Elizabeth for StoryCorps in 2008, he said he had been pleased that when he moved his family to New Haven in the early 1980s, his daughters were taking the bus to public schools.
“I put perhaps a million kids on school buses” he said, referring to his involvement in school desegregation cases that led to mandatory busing. “To have my daughters take school buses voluntarily and enjoy it makes me feel better.”