Aquino was assassinated on August 21, 1983, when he was shot in the head after returning to the country.
After the assassination of opposition leader former Senator Benigno Aquino, Jr. in 1983, the opposition ran for the Regular Batasang Pambansa under the United Nationalist Democratic Organization (UNIDO) and the Partido Demokratikong Pilipino-Lakas ng Bayan (PDP-LABAN) against the ruling Kilusang Bagong Lipunan of Ferdinand Marcos.