Senator Ben Cardin of Maryland, a long-serving Democrat, announced his retirement on Monday, clearing the way for highly competitive primaries to replace him in 2024, especially among Democrats in a deep-blue state.
Maryland’s liberal-leaning voters have not sent a Republican to the U.S. Senate since 1980, and the eight-member congressional delegation includes just one member of the G.O.P.
“I have run my last election and will not be on the ballot in 2024, but there is still much work to be done,” Mr. Cardin, 79, said in a statement. “During the next two years, I will continue to travel around the state, listening to Marylanders and responding to their needs.”
High-profile Maryland Democrats who could be in the mix to replace Mr. Cardin include Representatives Jamie Raskin and David Trone, and Angela Alsobrooks, the executive of Prince George’s County.
On the Republican side, there is already speculation about whether Larry Hogan, a popular former governor who in March said he would not run for president, will make a bid.
In an interview, Mr. Cardin declined to endorse a successor, but he said he was confident Democrats would hold the seat.
His election to the Senate in 2006 made him the third straight representative from Maryland’s Third Congressional District to join the chamber. The House seat is now held by John Sarbanes, a son of Paul Sarbanes, the senator who preceded Mr. Cardin.
Mr. Cardin was named last month by Senator Chuck Schumer, the majority leader, to serve on the Judiciary Committee as a temporary replacement for Senator Dianne Feinstein of California, who is on leave recovering from shingles, but Republicans have blocked the move. Without her vote, Democrats have been unable to advance stalled judicial nominations.
In a video announcing his retirement that he recorded with his wife, Myrna Cardin, Mr. Cardin touched on highlights of a career that includes enacting the Magnitsky sanctions, international penalties aimed at violators of human rights, and environmental protections for Chesapeake Bay.
Much of his motivation through his 58 years in elected office, Mr. Cardin said in the video, “comes back to tzedakah, part of our tradition as Jews to help those that are less fortunate.”
Mr. Cardin, who was speaker of the Maryland House of Delegates before being elected to Congress, said in the interview on Monday that he hopes to focus his final two years in the Senate on helping small businesses.
