How the Senate G.O.P. Scored a Top Recruit and Widened Its Path to a Majority

Larry Hogan might not be running for Senate this year but for a letter he received in early January.

The popular former Republican governor of Maryland had rebuffed years of entreaties and lobbying from a parade of powerful Republicans. But when he received an emailed letter from a lifelong Maryland resident on Jan. 8 making less an appeal to partisanship than a call to public service, Mr. Hogan responded within an hour — with an invitation via an aide for a private meeting in Annapolis.

The letter’s author, Darin Thacker, was no ordinary constituent. He’s the chief of staff to the chairman of the Senate G.O.P.’s campaign arm.

Once Mr. Hogan had cracked open what had seemed a shut door, Mr. Thacker quickly informed his boss of his personal outreach, setting in motion a frantic three-week sprint of private meetings and polling. Mr. Hogan ultimately made a dramatic surprise entrance into the race hours before a Feb. 9 filing deadline. The decision delivered a genuine jolt to a Senate landscape that was already heavily tilted toward Republicans in 2024.

“Without that letter, I don’t think Larry Hogan is in the race,” said Mr. Thacker’s boss, Senator Steve Daines of Montana, chairman of the National Republican Senatorial Committee. People close to Mr. Hogan agreed.

The Hogan recruitment served as a capstone to months of quiet success for Mr. Daines and Senate Republicans, after more than a decade filled with recruiting disappointments, misfires and downright self-sabotage.