The math, more than politics, may hold the key to Vice President Sara Duterte’s political future. And the numbers could be settled within the next two weeks, when the Senate, sitting as an impeachment tribunal, decides which denominator should be used in determining the votes needed for conviction or acquittal.
It sounds like a math professor’s problem. It is anything but. In an impeachment trial, the denominator can be destiny.
At the heart of Senator Erwin Tulfo’s motion is a deceptively simple question. When the Constitution requires two-thirds of “all the Members of the Senate” to convict, does that mean all 24 senators, even those who cannot participate, or only those legally able to take part in the proceedings?
That is not a technical footnote.
The denominator sets the constitutional hurdle itself. It determines how difficult it is to remove a sitting president or vice president while also determining whether impeachment remains a functioning instrument of accountability.
Keep the denominator at 24, and 16 votes are needed to convict, regardless of how many senators can actually vote. Conversely, 9 votes are needed to acquit.
Tulfo’s concern is that an absent senator becomes a peculiar kind of political arithmetic: unable to cast a vote, yet still counted in the number of votes required. Taken to an extreme, he warns, that could amount to an “acquittal by default.”
But Tulfo is not necessarily asking for a lower bar. He is asking the Senate to decide who belongs behind the bar in the first place. If the base changes, the numbers for both conviction and acquittal change with it.
Senator Pia Cayetano has cautioned against treating Avelino v. Cuenco as settled Senate doctrine, while Senator Robin Padilla has offered the constitutional equivalent of a red flag: The charter cannot be recalibrated simply because the numbers have become inconvenient.
Both arguments deserve serious attention.
Impeachment should be difficult. A high threshold protects an elected official from removal by a transient political majority. But difficulty should not quietly become impossibility, either.
A Constitution designed to enforce accountability cannot sensibly turn into a mechanism where the absence of senators decides what their votes might have been.
That is why the Senate is right to bring in constitutional experts and hear both sides before voting.
First, settle the denominator.
Then count the votes.
Otherwise, the Senate risks discovering that in constitutional law, as in mathematics, getting the first number wrong can make every number after it meaningless.
And this question may not end on the Senate floor. Whatever interpretation prevails could eventually reach the Supreme Court, where the arithmetic of one impeachment may become jurisprudence for the next.
The Constitution deserves more than convenient math. It deserves an answer that can survive the numbers, the politics, and the passage of time.
