
De La Salle-College of Saint Benilde (DLS-CSB) School of Diplomacy and Governance (SDG) part-time professor Gabrielle Tañada
The Constitution does not say that 16 senators are required to convict an impeached official.
Article XI, Section 3(6) of the 1987 Constitution instead provides that “[n]o person shall be convicted without the concurrence of two-thirds of all the Members of the Senate.” Article VI, Section 2, meanwhile, provides that the Senate “shall be composed of 24 Senators.”
The arithmetic appears straightforward: two-thirds of twenty-four is sixteen. Yet the present impeachment proceedings raise a question that arithmetic alone cannot answer: Who counts as part of “all the Members of the Senate”?
The Senate Impeachment Court invited four retired Supreme Court magistrates as amici curiae (“friends of the court”) on the issue. Retired Chief Justices Artemio Panganiban, Reynato Puno, and Hilario Davide Jr., through differing approaches, took the position that the number required for conviction need not invariably remain 16. Retired Associate Justice Adolfo Azcuna maintained that all 24 incumbent senators constitute the denominator. Significantly, Davide and Azcuna were both members of the 1986 Constitutional Commission, yet interpreted the same language differently.
A fixed denominator treats membership as legal status: A senator remains part of “all the Members” even when unable to participate. Its strength is certainty; its weakness is that a senator incapable of voting would still count toward the 24-member denominator.
A variable denominator instead prioritizes the institution’s capacity to function. Its difficulty is determining where the exception ends. Should death, vacancy, physical incapacity, legal disability, recusal, voluntary absence, and deliberate non-participation have the same constitutional consequence? Who decides—and by what standard?
There is a useful parallel in corporate law. Sections 13 and 37 of the Revised Corporation Code illustrate that a corporation’s legally constituted capital structure does not simply change because the circumstances of an individual stockholder change; altering authorized capital requires a process prescribed by law. The analogy is imperfect, but its underlying distinction matters: A change in the status of a person within an institution does not necessarily change the legal structure of the institution itself.
The same distinction should inform the Senate. Article VI does not say that the Senate consists of however many senators are presently capable of voting. It prescribes 24. Read alongside Article XI’s requirement of two-thirds of “all the Members,” 24—not the number capable of participating on a particular day—is therefore the stronger constitutional starting point.
Incapacity need not be irrelevant. But if it can alter the denominator, the law must distinguish among different forms of incapacity and determine who may be excluded, for what reason, through what process, and under whose authority. Otherwise, a constitutional threshold risks becoming a situational one.
For lawyers, this concerns constitutional interpretation and institutional authority. For development practitioners, it concerns predictability, representation, and confidence in the rules of political accountability. The Constitution chose not to constitutionalize the number 16; it constitutionalized a fraction—two-thirds of all the Members—against a Senate constitutionally composed of 24.
The next impeachment may involve different incapacities, personalities, and political interests. Whatever rule governs today must therefore remain intelligible when those circumstances change.
Rather than focusing on whether a rule resolves the circumstances of this occasion, the better test of constitutional interpretation is whether it remains a rule when the occasion changes.




