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.
The state’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 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.