Estrada's successor, Gloria Macapagal Arroyo, was a vocal opponent of the death penalty and also approved a moratorium on the carrying out of capital punishment. This prohibition was later formalized into a full law when the Congress passed Republic Act 9346 in 2006. The next year, the Philippines became a party to the Second Optional Protocol to the International Covenant on Civil and Political Rights regarding the abolition of the death penalty. President Arroyo controversially pardoned many prisoners during her presidency, including a 2009 pardon for all remaining felons convicted for the 1983 assassination of former Senator and opposition leader Benigno Aquino Jr.