“We, the sovereign Filipino people, imploring the aid of Almighty God, in order to build a just and humane society and establish a Government that shall embody our ideals and aspirations, promote the common good, conserve and develop our patrimony, and secure to ourselves and our posterity the blessings of independence and democracy under the rule of law and a regime of truth, justice, freedom, love, equality, and peace, do ordain and promulgate this Constitution.” Preamble
After Marcos’ overthrow in the 1986 EDSA People Power Revolution, there was a need to replace the 1973 Constitution which was in use during the dictatorship. President Corazon C. Aquino then issued Proclamation No. 9 on 23 April 1986, ordering the formation of a Constitutional Commission (ConCom). Chaired by Cecilia Munoz Palma, the ConCom commenced work on 2 June 1986 at the Batasang Pambansa.
In the meantime, the Aquino administration used the 1986 Freedom Constitution, which was actually a set of major amendments to the 1973 Constitution.
The new constitution was completed on 12 October 1986. The draft was presented to Aquino three days later, marking the start of a massive nationwide information campaign. A plebiscite for its ratification was held on 2 February 1987, with around 17 million voters in favor while only 5 million were against its ratification. The new constitution was then proclaimed as ratified and in effect on 11 February 1987, with the government and the military pledging their allegiance.
However, the plebiscite date of 2 February 1987 is taken as the official date of ratification due to the Supreme Court ruling in the De Leon vs. Esguerra (153 SCRA 602) case on the term of several barangay officials in Brgy. Dolores, Taytay, Rizal. In the ruling, the Supreme Court took the plebiscite date as the basis for ruling in favor of the petitioners.
Source: http://en.wikipilipinas.org/ (Click to read more)