Ronald L. Feinman is the author of Assassinations, Threats, and the American Presidency: From Andrew Jackson to Barack Obama (Rowman Littlefield Publishers, 2015).  A paperback edition is now available.

California Democratic Senator Dianne Feinstein has already announced that she will retire at age 91 when her current term ends in 2024. While Feinstein’s absence from the Senate and from her post on the Judiciary Committee have raised calls for her to resign immediately, as of publication, she has not done so. An immediate resignation would allow Governor Gavin Newsom to appoint her successor, but if Feinstein finishes her term there will be a fierce battle among many California Democrats for what will be an assured Democratic seat into the foreseeable future.

Whenever Feinstein retires, there will only be a handful of US Senators who served since the popular election of senators was instituted by the 17^th Amendment in 1913, to have served at an older age. None of the senators who were elected by state legislatures before 1913 reached that age while in office.

The advanced age of Senators is by no means confined to Feinstein. Current Iowa Republican Chuck Grassley is 3 months younger than Feinstein, and was just reelected by his constituents in 2022 to another six-year term. If he finishes the term at the beginning of 2029, he will be past 95 years of age, making him the second oldest US Senator in American history.

Grassley would also move into a tie for third place for years of service with Vermont Democrat Patrick Leahy, who retired in 2023 after 48 years of service (though at the relatively young age of 82).  Grassley will have passed both South Carolina Republican Strom Thurmond (who served more than 47 years) and Massachusetts Democrat Ted Kennedy of Massachusetts  (nearly 47 years), if he completes his term.

Beyond Feinstein and Grassley, only a few others have reached their 90s as members of the US Senate.

The oldest was South Carolina Republican Senator Strom Thurmond, who left office at 100 years and 29 days in 2004, and died six months later.  He was the 4^th longest serving Senator with more than 47 years in office, and he was President Pro Tempore for about six years in the mid and late 1990s, just three heartbeats away from the presidency.

Next oldest was Rhode Island Democratic Senator Theodore F. Green, who left office at 93 years and three months in 1961 after four terms in the Senate. First taking office in 1937 at age 69, Green lived past 98 years of age, dying in 1966.

The third oldest was West Virginia Democratic Senator Robert F. Byrd, who died in office at age 92 years and seven months, serving 51.5 years in office from 1959-2010, the longest service of any US Senator. He served as President Pro Tempore for more than ten years, most of it in his last years in the Senate.

The fourth oldest was Arizona Democratic Senator Carl Hayden, who left office at 91 years and three months, after serving 41 years and ten months from 1927-1969. This was after serving in the House of Representatives for 14 years, dating from the beginning of Arizona statehood in 1912.  For a period of 14 months between 1963 and 1965, Hayden was the second in line for the Presidency as President Pro Tempore of the Senate after the assassination of John F. Kennedy. He was 86 years of age at that time. He died in 1972 past the age of 94, and is the 8^th longest serving US Senator..

Fifth oldest was Hawaii Democratic Senator Daniel K. Inouye, who served 49 years and 11.5 months in the Senate, from 1959-2012, dying in office at age 88 and three months, and having served as President Pro Tempore of the Senate from 2010-2012.  His service in the Senate was the second longest, behind Robert Byrd.

Feinstein has already passed Inouye in age, as she turns 90 in June of this year. Chuck Grassley will reach the same age in September of this year, and if he finishes his term in 2029, at age 95, only will be behind Strom Thurmond in age in the Senate.

Although many progressives lament what they call a “gerontocracy” in the Senate and other parts of the government, it’s ironic that a progressive candidate in a possible scrum to succeed Feinstein in 2024 would take office past the age of 78.

This would be Democratic Congresswoman Barbara Lee of California. Although she has represented Oakland and the East Bay in the house since 1988, Lee is most famous as the only member of either house of Congress to vote against support of the AUMF (Authorization For The Use Of Military Force) resolution following the September 11, 2001 terrorist attacks against the World Trade Center and the Pentagon.  Lee was honored in my article of March 4, 2022 on two antiwar Congresswomen, Jeannette Rankin and Barbara Lee on the History News Network website.

The only Senators previously inaugurated for service in the US Senate at age 78 or higher took office by short-term appointment, not by election. 

The oldest was Georgia Democratic Senator Rebecca Latimer Felton, who served exactly one day by appointment at age 87 and five months in November 1922, and was the first woman to serve in the Senate.  Interestingly, she was a supporter of women’s suffrage and feminism, but also was a white supremacist, Congress’s last former slave owner, and a strong supporter of lynching.  She lived to age 94.

The other such appointment was Texas Democratic Senator Andrew Houston, who served by appointment for three months at age 86 in 1941. This makes him the oldest man ever to enter the Senate; Houston died in office a few days after his 87^th birthday.  Interestingly, he was the son of the famous Texas statesman Sam Houston, who had been the President of the Republic of Texas. 
So were Barbara Lee to be elected and be sworn in the US Senate in 2025, she would be the oldest first-time elected Senator in American history, and only the third African American woman ever elected to the Senate, after Illinois Democrat Carol Moseley Braun and California Democrat Kamala Harris, who is of course now the vice president. 

Lee’s first term would end with her aged more than 84. Lee has said she would only seek one term, but the advanced age of so many other senators, including Feinstein, shows that the lure of remaining in office is strong. Should Senator Lee remain in good health, it’s not beyond possibility that she could seek reelection in 2030.