Robert J. McCarthy, a powerful political fundraiser and San Francisco resident, died Sunday of cancer at the age of 61. McCarthy died in his home in the St. Francis Wood neighborhood. McCarthy attended Santa Clara University and graduated from the University of Chicago’s law school. He started practicing law in the 1970s with the San Francisco District Attorney’s Office and eventually became chief deputy district attorney. McCarthy helped to elect Sens. Dianne Feinstein and Barbara Boxer, Attorney General Jerry Brown, House Speaker Nancy Pelosi and former Mayor Willie Brown.