By: Atty. Gregorio B. Austral, CPA
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A two-thirds requirement is meaningful only when its denominator is identified. Article VII, Section 21 of the 1987 Constitution provides that no treaty or international agreement shall be valid and effective unless concurred in by “at least two-thirds of all the Members of the Senate.” The constitutional basis is therefore the entire membership of the Senate—not merely the Senators present, those voting, or those who happen to hold office on the day of the vote.
The Supreme Court applied that rule in Bayan v. Zamora, G.R. Nos. 138570, 138572, 138587, 138680, and 138698, October 10, 2000, which involved the Visiting Forces Agreement. The Court held that the Senate concurrence contemplated by Article XVIII, Section 25, concerning agreements involving foreign military bases, troops, or facilities, must be read together with the general requirement in Article VII, Section 21. “Duly concurred in by the Senate” therefore means concurrence by at least two-thirds of all the Members of the Senate.
The computation in Bayan was precise. The Constitution provides for a Senate composed of 24 Senators; two-thirds of 24 is 16. The Court held that at least 16 favorable votes satisfied the constitutional requirement. The fact that only 23 Senators were incumbent when the vote was taken did not alter the controlling constitutional denominator: two-thirds of the Senate’s 24-member composition, or at least 16 affirmative votes.
The same constitutional basis governed the Senate’s concurrence in the Rome Statute, discussed in Pangilinan v. Cayetano, G.R. Nos. 238875, 239483, and 240954, March 16, 2021. The Supreme Court described Article VII, Section 21 as requiring Senate concurrence by at least two-thirds of all Senators before a treaty or international agreement may be considered valid and effective in the Philippines. The case record further states that the Senate approved Resolution No. 546 by a vote of 17–1 and that the Philippines thereafter deposited its instrument of ratification.
Pangilinan also emphasized the mandatory character of the requirement. The constitutional provision is couched in negative terms: no treaty or international agreement shall be valid and effective unless the required Senate concurrence is obtained. The case thus confirms that the two-thirds vote is not a procedural preference or a majority-of-those-present rule; it is a constitutional condition for domestic validity and effectiveness.
The denominator changes when a two-thirds requirement is created by statute rather than by the Constitution. Republic Act No. 9054, for example, required two-thirds of the Members of the House of Representatives and of the Senate, voting separately, for congressional reamendment or revision of the ARMM Organic Act; for a proposal initiated by the Regional Assembly, the Assembly first had to act by three-fourths of all its Members.
The cases therefore require attention not only to the fraction but also to its legal source: under Bayan and Pangilinan, the denominator is fixed by the Constitution’s reference to all Members of the Senate, while under R.A. No. 9054 the stated statutory denominator was the membership of each House voting separately.