He was the leader of the Movement of Concerned Citizens for Civil Liberties (MCCCL), which organized a series of rallies from 1971 to 1972. The most massive of these rallies involved 50,000 protestors and was held on 21 September 1972, shortly before the imposition of martial law by the Marcos dictatorship. During this rally, protestors denounced the infamous "Oplan Sagittarius", the devious operation plan by Marcos to declare martial law. Sen. Benigno ""Ninoy"" Aquino exposed the Oplan Sagittarius scandal earlier in a September 13 speech, and spoke to the Senate on September 21, the same day that the MCCCL held their exceptionally large rally at Plaza Miranda. Marcos reacted with fear of deposition and immediately finalized Proclamation No. 1081, which declared nationwide martial law at 8:00 p.m. later that evening. Exactly the next day on September 22, 1972 at 8:00 p.m., Defense Minister Juan Ponce Enrile was told to exit his car near Wack-Wack village. Another vehicle carrying gunmen arrived and stopped near an electrical post, right beside Enrile's vehicle. They then alighted from their vehicle and began to fire at the large sedan of Enrile to give an impression of a terrorist ambush, setting the stage for Marcos's theatrical television announcement.