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, Hogan responded within an hour — with an invitation via an aide for a private meeting in Annapolis. The letter’