Democratic Sen. Ben Cardin of Maryland won't run for reelection

Democratic Sen. Ben Cardin of Maryland won't seek reelection in 2024, opening a rare U.S. Senate seat in the state that neighbors Washington, D.C.

"I am proud of all I have done for Maryland," Cardin said in a statement. "I have given my heart and soul to our great state, and I thank Marylanders for trusting me as your representative for all these years. ... I have run my last election and will not be on the ballot in 2024, but there is still much work to be done." 

Cardin, 79, has spent most of his adult life in politics, and first joined the U.S. Senate in 2007. He joined the U.S. House in 1987, and before that, he was the speaker of the Maryland House of Delegates. 

No one has announced a bid to replace Cardin yet, although all eyes will be on Rep. Jamie Raskin, who gained prominence during former President Donald Trump's impeachment trials and just completed chemotherapy for cancer. Raskin has a preliminary diagnosis of being "in remission" from lymphoma with a 90% prognosis of no relapse, he says. 

Former Maryland Gov. Larry Hogan, a moderate Republican who is still popular in the safe blue state, isn't running for president, but he's likely to be another name under consideration for a GOP candidate for Cardin's seat. 

Democrats currently hold a one-seat majority in the U.S. Senate, and they face steep odds in keeping the majority after the 2024 election. Republicans are only defending 10 seats and they are all in safe red states, while three Democrats are up for reelection in states won by Trump in 2020 (Ohio, West Virginia and Montana) and another five are up in swing states (Arizona, Michigan, Wisconsin, Pennsylvania and Virginia).