In Washington, impeachment debates often orbit around constitutional phrases like “high crimes and misdemeanors.” In Manila, the battle lines have sharpened around something more procedural but no less consequential: probable cause.

This week’s findings—linking the Commission on Audit (COA) and the National Bureau of Investigation (NBI) to allegations against Vice President Sara Duterte—have injected fresh urgency into a process that has already survived constitutional setbacks, Supreme Court intervention, and political brinkmanship.

At first glance, “probable cause” sounds like a modest legal hurdle. It is not. It is the moment when an allegation becomes an institutional belief.

And in the Philippines’ impeachment architecture, that moment belongs not to judges—but to politicians.

The House justice committee’s role is formally legal: to weigh evidence and determine whether there is a reasonable basis to proceed. But impeachment has never been purely legal. It is a hybrid proceeding, where evidentiary standards meet political incentives.

On one hand, lawmakers argue that findings by investigative bodies—particularly the NBI—“strengthen” the impeachment case, pointing to alleged criminal acts and misuse of funds.

On the other, the vice president’s camp has consistently framed the process as politically motivated, a continuation of an intensifying rift between the Duterte and Marcos camps.

Probable cause, then, becomes more than a legal test. It becomes a political signal.

A vote affirming it tells the public: this is serious enough to try.
A vote rejecting it says: this is not worth the nation’s time.

Hovering over the current proceedings is the Supreme Court’s 2025 decision voiding an earlier impeachment complaint against Duterte on procedural grounds, invoking due process and the one-year bar rule. That ruling did more than reset the clock. It raised the stakes.

Now, lawmakers are not merely deciding whether probable cause exists—they are doing so under the shadow of judicial scrutiny that has already shown a willingness to intervene.

The message from the Court was unmistakable: even impeachment must obey constitutional discipline.

The COA and NBI findings—reportedly pointing toward irregularities and possible liability—provide the kind of documentary backbone that impeachment complaints often lack.

But probable cause does not emerge from documents alone. It is constructed through narrative coherence: Do the allegations tell a believable story? Do the facts connect logically? Do they suggest not just irregularity—but culpability?

This is where impeachment differs sharply from criminal prosecution. In court, doubt favors the accused. In impeachment, persuasion favors momentum.

Ultimately, the debate over probable cause in the Duterte impeachment is less about one official and more about institutional credibility.

If the House finds probable cause too easily, impeachment risks becoming a weapon of factional warfare.

If it sets the bar too high, it risks becoming functionally impossible, even in the face of serious allegations.

The Constitution envisioned impeachment as a mechanism of accountability—not paralysis.

The real question

The question before lawmakers is not whether Sara Duterte is guilty. It is whether the evidence—COA findings, NBI recommendations, and sworn testimonies—crosses that crucial threshold: Is there enough here to justify putting the vice president on trial before the nation?

That is what probable cause demands.
Nothing more.
But certainly nothing less.