G.R. No. 89651 and G.R. No. 89965 November 10, 1989
Datu Firdausi I.Y. Abbas, et al. and Atty. Abdullah D. Mama-o vs. Commission on Elections and Hon. Guillermo C. Carague

FACTS

These consolidated petitions sought to enjoin the plebiscite scheduled for November 19, 1989, for the ratification of Republic Act No. 6734 , the Organic Act for the Autonomous Region in Muslim Mindanao (ARMM), and to declare the law unconstitutional. Petitioners, representing taxpayers and citizens of Mindanao, argued that R.A. No. 6734 violated constitutional provisions on autonomy and conflicted with the 1976 Tripoli Agreement between the Philippine government and the Moro National Liberation Front. They contended the law did not comply with the constitutional mandate for genuine autonomy, improperly limited the plebiscite area, and contained provisions that were ineffective or contradictory.
The respondents, the Commission on Elections and the Secretary of Budget and Management, defended the law’s constitutionality. They asserted that R.A. No. 6734 was enacted in faithful compliance with the directives under Article X of the 1987 Constitution , which for the first time provided a framework for creating autonomous regions. The Solicitor General argued that the Tripoli Agreement was not a binding international treaty ratified as required by the Constitution and thus could not serve as a legal standard to invalidate the Organic Act.

ISSUE

The primary issue was whether Republic Act No. 6734 , the Organic Act for the ARMM, was unconstitutional.

RULING

The Supreme Court dismissed the petitions, upholding the constitutionality of R.A. No. 6734 . The Court’s legal logic proceeded from two key principles. First, it declined to rule on the nature or binding effect of the Tripoli Agreement, finding such a determination unnecessary. The controlling standard for evaluating the Organic Act was the 1987 Constitution itself, which expressly provided for the creation of autonomous regions and outlined the process and powers therein. Any perceived conflict between the statute and the Tripoli Agreement was therefore irrelevant to the constitutional inquiry.
Second, the Court applied the strong presumption of constitutionality in favor of every law. It systematically examined petitioners’ specific challenges—including those regarding the plebiscite mechanics, the substantive powers granted to the region, and the law’s effectivity—and found no clear and convincing evidence that R.A. No. 6734 contravened the Constitution. The Court held that the law was a legitimate exercise of legislative discretion pursuant to the constitutional mandate. It was crafted with the assistance of a regional consultative commission and provided a framework for autonomy consistent with national sovereignty. Petitioners failed to overcome the presumption of validity, as their arguments did not establish a clear constitutional infirmity. Consequently, the plebiscite could proceed as scheduled.