Vice President Sara Duterte's defense and House prosecutors laid out starkly different visions of the Senate's impeachment powers on Wednesday, with one warning that impeachment cannot override constitutional rights and the other insisting the court cannot uncover the truth without access to the vice president's financial records.

In an opening argument before the impeachment court, defense lawyer Michael Poa said the prosecution's requests for subpoenas and subpoena duces tecum amounted to a "fishing expedition," contending they sought evidence first before establishing proof for the accusations against Duterte.

"Impeachment is not a magic word or a magic wand that one can just wave to transform an illegal act into a legal act, to transform unlawful access to lawful access," Poa told senator-judges. 

At issue are motions by the House prosecution panel seeking subpoenas ordering the Bureau of Internal Revenue (BIR), the Anti-Money Laundering Council (AMLC), banks and other institutions to produce Duterte's tax records, bank documents and AMLC reports, as well as records relating to her husband, lawyer Manases Carpio.

Those documents underpin Article II of the Articles of Impeachment, which accuses Duterte of amassing wealth grossly disproportionate to her lawful income, failing to disclose assets in her Statements of Assets, Liabilities and Net Worth (SALNs) from 2022 to 2025, and engaging in business prohibited by the Constitution while serving as vice president.

Defense lawyer Michael Poa argued that granting the requests would allow prosecutors to search first for evidence instead of proving their allegations.

"When a subpoena becomes oppressive, when it is unreasonable, and when it is merely issued for the very purpose that there is a hope that somewhere, somehow, something incriminating will come out, it ceases to be an instrument of justice," Poa said.

Corona precedent vs Duterte ruling

Beneath the dispute over bank records lay a broader constitutional question that could shape the remainder of Duterte's trial: How much power does an impeachment court have to compel evidence, and who gets to define its limits?

Leading the prosecution's arguments, Akbayan Rep. Chel Diokno said the Constitution grants the Senate the "sole power" to try and decide impeachment cases, making it the final arbiter of what evidence is relevant and what conduct constitutes an impeachable offense. 

He cited the Supreme Court's rulings in Francisco v. House of Representatives and Gutierrez v. House of Representatives, which described those questions as political matters entrusted to Congress rather than the judiciary.

To reinforce that point, Diokno invoked the Senate's 2012 impeachment trial of then Chief Justice Renato Corona, where senator-judges ordered banks to produce Corona's account records—including transactions before he became chief justice—to determine whether he had concealed wealth in his Statements of Assets, Liabilities and Net Worth (SALNs). 

The Senate ultimately admitted the records into evidence and convicted Corona, establishing what prosecutors describe as the clearest precedent for the impeachment court's subpoena powers. 

House prosecutor Chel Diokno argued the precedent shows the Senate's constitutional power to compel evidence cannot be curtailed by ordinary laws on bank secrecy or confidentiality. 

But Duterte's lawyers argued the Corona trial no longer provides the controlling legal framework.

They instead pointed to the Supreme Court's 2026 ruling in Duterte v. House of Representatives, a decision that voided an earlier impeachment complaint against the vice president for violating the Constitution's one-year bar rule and emphasized that due process governs every stage of impeachment. 

While the case did not involve subpoenas or financial records, the Court emphasized that due process governs every stage of impeachment and clarified that impeachable offenses are acts committed by a public officer while occupying an impeachable office.

For Poa, that clarification fundamentally limits the prosecution's request. Because the subpoenas seek financial records dating back to 2007—when Duterte was Davao City's vice mayor—they would reach beyond the constitutional scope of impeachment and amount to an impermissible search for evidence of conduct that, even if unlawful, should instead be addressed through ordinary criminal or civil proceedings.

The Senate impeachment court has yet to rule on the competing motions as of press time. 

Its decision will determine whether prosecutors can obtain fresh financial evidence or must rely largely on records already introduced during the House impeachment inquiry as the trial moves to its evidentiary phase.###