William Anthony "Tough Tony" Boyle (December 1, 1904 – May 31, 1985), a murder-for-hire conspirator, miner, and union representative from Montana, became president of the United Mine Workers of America union in 1963, serving until 1972. He was convicted in 1974 of charges of conspiracy in the murder of opponent Joseph A. Yablonski, his wife Margaret, and their daughter Charlotte, on New Year's Eve, December 31, 1969. After an appeal, his conviction and sentence were upheld at a second trial; he was sentenced to three life terms and died while still incarcerated.