It remains unclear who will ultimately sit as presiding officer of the impeachment court that will try the case of Vice President Sara Duterte, which will start two weeks from now.

By default, Senate President Sherwin Gatchalian will be the presiding officer, following the Senate Rules of Procedure on Impeachment Trials.

However, Senator Panfilo Lacson said last week at the sidelines of the Senate special session that Senator Francis “Chiz” Escudero may return as presiding officer, as per their consensus. But Gatchalian recently said that this is not yet final.

Meanwhile, Senator Robinhood Padilla said the Constitution is clear that the Senate President should preside over the impeachment trial. He stressed that replacing the Senate President during the impeachment proceedings could raise constitutional questions.

"Ang Constitution malinaw na siya dapat (The Constitution is clear that it should be him [Gatchalian]),” he said.

When asked whether he personally prefers Gatchalian to preside over the trial, Padilla replied that the Constitution leaves little room for interpretation.

“Dapat. Kasi yun ang nasa Constitution (That's how it should be. That's what's in the Constitution),” he said, adding that while the Chief Justice presides over impeachment proceedings involving the President, the Senate President presides in cases involving lower-ranking officials.

Padilla also said the minority bloc would likely oppose any move to install another senator as presiding officer if such a proposal is formally raised.

Yet the 1987 Constitution is silent on all other impeachable officials, such as the Vice President, Supreme Court Justices, or the Ombudsman, on who must physically sit in the presiding chair. The designation of the Senate President as the presiding officer in non-presidential trials comes from internal rules rather than explicit constitutional text.

What it clearly states is that: "When the President of the Philippines is on trial, the Chief Justice of the Supreme Court shall preside, but shall not vote."

Under Article XI, Section 3(8), the Constitution grants the Senate the power to "promulgate its rules of procedure" for impeachment.

The Senate recently amended its internal impeachment rules through Senate Resolution No. 430, which amended Rule II to officially allow a majority vote of the members present to elect another senator to preside over non-presidential impeachment proceedings.

Whether or not the Senate Impeachment Court will let Gatchalian or Escudero preside over Duterte's trial remains to be seen.