COLUMBIA, S.C.—State Sen. Hugh Leatherman, South Carolina’s oldest and most powerful state lawmaker, died Friday at the age of 90. Leatherman died at his home in Florence, his office said, after being diagnosed with an inoperable cancer. As he entered hospice care last month, Leatherman’s staff began notifying lawmakers that the nonagenarian Republican had been hospitalized with severe abdominal pain, and that doctors discovered the cancer while removing parts of his intestine. “Ever the stubborn optimist,” Leatherman continued to work, drafting legislation, and receiving budget briefings for the upcoming legislative session, according to a family statement. “While his passing brings us great sorrow, we take solace and joy knowing that up until his last days, he was active in the Florence community, and continued serving the people of Florence and South Carolina,” they wrote. Leatherman was in his 11th term and among the longest-serving lawmakers in South Carolina’s Legislature. First …