Larry Hogan Will Run for Senate in Maryland

Larry Hogan, the popular Republican former governor of Maryland, announced on Friday that he would run for the state’s open Senate seat, a surprising move that immediately made the state a top battleground for control of the chamber.

“I am running for the United States Senate — not to serve one party — but to stand up to both parties, fight for Maryland, and fix our nation’s broken politics,” Mr. Hogan wrote on X. “It’s what I did as Maryland’s governor, and it’s exactly how I’ll serve Maryland in the Senate. Let’s get back to work.”

Mr. Hogan has been one of his party’s most vocal critics of former President Donald J. Trump and has endorsed former Gov. Nikki Haley of South Carolina for the Republican nomination. He also had been viewed as a possible presidential candidate for No Labels, a group for which he played a leadership role as it explored a third-party bid in 2024.

Senator Steve Daines, a Montana Republican and the chairman of the National Republican Senatorial Committee, welcomed Mr. Hogan into the race, saying he was “a great leader for Maryland, and that’s why he remains overwhelmingly popular in the state.”

Mr. Hogan previously said he would not run for the seat, which is currently held by Senator Benjamin L. Cardin, a Democrat who declined to seek re-election.

Democrats in the race include Representative David Trone — the founder of Total Wine & More, the nation’s largest independent wine retailer — who has support from Representative Hakeem Jeffries, the House minority leader. Angela Alsobrooks, an elected county executive in Prince George’s County, Md., is also seeking the Democratic nomination and she has been endorsed by Gov. Wes Moore.

While Mr. Hogan has a moderate record, Democrats are painting the race as a battle for the Senate.

“A vote for Republican Larry Hogan is a vote to make Mitch McConnell majority leader and turn the Senate over to Republicans so they can pass a national abortion ban,” said Maeve Coyle, a spokeswoman for the Democratic Senatorial Campaign Committee. “Democrats have won every statewide federal election in Maryland for 44 years and 2024 will be no different.”

Mr. Hogan, a former real estate executive, won the governor’s office in a surprise victory in 2014 and served for eight years, during which he also had advanced lymphatic cancer.

His campaign for the Senate is expected to strengthen the Republican bid to win the majority. The party is expected to gain a seat in West Virginia after Senator Joe Manchin III, a Democrat, announced he would not seek re-election, and it is also mounting competitive campaigns in Montana, Ohio and Arizona — all of which would be Republican pickups.

Republicans need to flip two seats to win back power if President Biden is re-elected, but just one if Mr. Trump or another Republican captures the White House.