A Cairo court sentenced Egypt’s deposed autocrat Hosni Mubarak and his two sons to three years in prison on corruption charges on Saturday—a punishment that authorities may deem as having already been served but one which, if it withstands appeal, would officially establish Mubarak as a convicted criminal years after the 2011 popular uprising that toppled him. The case—dubbed the “presidential palaces” affair by the Egyptian media—was a retrial charging that Mubarak and sons embezzled millions of dollars’ worth of state funds over the course of a decade, diverting money meant to pay for renovating and maintaining presidential palaces to...