Long before Donald Trump elevated his primary bid for governor, Del. Dan Cox was a polite backbencher in the Republican super-minority, building his reputation in Annapolis as a thoughtful yet inflexible lawyer whose legislation rarely passed. Cox (R-Frederick) held the door for Democratic colleagues, earnestly suggested an acerbic GOP friend pick up “How to Win Friends and Influence People” — and championed bills often far outside Maryland’s political mainstream. “He was on the typical freshman path, finding his way,” said House Minority Leader Jason C. Buckel (R-Allegany), who supported Cox’s primary opponent. Then, “Dan’s sense of self and sense of himself as legislator really changed.”