Spain's governing Socialists on Saturday named Alfredo Perez Rubalcaba as their candidate for prime minister in general elections due by March 2012, his campaign team announced. Rubalcaba quit his post as interior minister on Friday to lead the Socialists into the elections, which the conservative opposition Popular Party is expected to win by a landslide in the midst of a deep economic crisis. Spanish Prime Minister Jose Luis Rodriguez Zapatero is not seeking a third term as leader and has backed the 59-year-old Rubalcaba's candidacy.