Former Philippine president Joseph Estrada is escorted by a policeman after filing his certificate of candidacy at the Commission on Elections (COMELEC) in Manila, Tuesday. — ReutersMANILA — Ousted Philippine president Joseph Estrada filed his candidacy Tuesday for mayor of Manila, joining thousands of candidates in midterm elections that will be dominated by political dynasties, celebrities and the rich and powerful. The polls scheduled for May 13, 2013, illustrate the most obvious streak of Philippine politics: It's a family affair. Among those expected to run again is Imelda Marcos, widow of dictator Ferdinand Marcos, who is among candidates for 286 congressional seats. Her daughter, Imee, will try to keep her seat as governor of their northern home province of Ilocos Norte. Her son, Ferdinand Marcos Jr., is already a senator. Estrada, 75, who is challenging his former ally, incumbent Mayor Alfredo Lim, moved into a house in Manila in May to establish residency there. Estrada's eldest son is also a senator and another wants to join him, along with the sons of two last-term senators. Among those contesting half of the 24 seats in the Senate is a congresswoman who is the wife of an outgoing senator. Also, a brother of another senator is seeking re-election. A cousin of President Benigno Aquino III, Paolo Benigno Aquino, is on the administration's senatorial slate. Their aunt, Margarita Cojuangco, is running for the Senate with the opposition. Boxing champion and incumbent Representative Manny Pacquiao has filed for re-election. — AP