1. ARTICLE II HAS FORMALLY STARTED

Article II accuses Duterte of amassing unexplained wealth, making false or incomplete declarations in her SALNs, and keeping interests in businesses while holding public office. Those are allegations in the impeachment case, not findings of guilt.

The prosecution began this stage with Tang instead of immediately presenting Duterte's SALNs, company records or bank documents. Its apparent purpose was to give the impeachment court a legal map before asking senator-judges to examine the paper trail. That map matters because the prosecution cannot prove its case by placing a large number beside Duterte's name. It must establish what property, financial interest or transaction is connected to her, when it was acquired or made, what her lawful income was during the relevant period, and why the difference cannot be satisfactorily explained.

The defense is entitled to challenge every part of that chain. It can dispute ownership, authenticity, dates, calculations and the meaning of the records. It can also present lawful sources of money or argue that the evidence does not belong in an impeachment trial.

2. TANG EXPLAINED THE RULES, NOT DUTERTE'S BANK RECORDS

Tang led the Sandiganbayan, the court that hears graft and corruption cases involving public officials. The prosecution presented her as an expert witness to explain concepts tied to public accountability, SALNs, beneficial ownership and unexplained or illegally acquired wealth.

That gives her testimony weight, but it also sets a clear limit. She was not presented as the custodian of Duterte's SALNs, the keeper of corporate files or the officer who traced the Vice President's bank transactions. She could explain how the law approaches those records. Her testimony alone could not establish that a particular account, property or company belongs to Duterte, or that money passing through an account came from an illegal source.

Senator-judge Raffy Tulfo raised a practical question: would Tang's testimony be more useful after the documentary evidence has been presented, when the legal concepts could be applied to the actual records? That question goes to the order and usefulness of the evidence, not Duterte's guilt or innocence.

3. HIDDEN, UNEXPLAINED AND ILL-GOTTEN WEALTH ARE NOT THE SAME THING

The hearing spent time separating terms that are often carelessly treated as synonyms.

Hidden wealth generally refers to an asset or financial interest that was concealed, omitted or placed under another name. But concealment by itself does not automatically prove that the money came from crime. Unexplained wealth usually involves property or spending that appears plainly out of proportion to a public official's lawful income and has not been satisfactorily accounted for under the applicable legal process. Ill-gotten wealth is a stronger accusation: it points to wealth allegedly acquired through abuse of office, misuse of public funds or another unlawful act.

Beneficial ownership is also important. The name written on a title or company record may not always identify the person who ultimately owns, controls or benefits from the asset. But beneficial ownership must still be established with evidence. It cannot simply be assumed because people are related, associated in business or politically connected.

The same caution applies to SALNs. A missing or inaccurate entry can be relevant and serious, but it does not automatically prove an impeachable offense, a crime or a right to forfeit property. The nature of the omission, the official's explanation and the surrounding evidence all matter.

4. THE DEFENSE FOUGHT HER APPEARANCE AND TESTED HER IMPARTIALITY

Duterte's lawyers tried to exclude Tang's testimony, arguing that presenting her violated due process because she was not properly included in the pretrial order. The prosecution defended her appearance as necessary to explain the public-accountability framework. Her examination and cross-examination proceeded despite the objection.

During cross-examination, defense lawyer Mark Vinluan questioned Tang about possible political leanings and personal motives. He asked whether she was anti-Duterte, whether she was a Kakampink, and whether she had been disappointed that former President Rodrigo Duterte did not appoint her to the Supreme Court. Tang denied the suggestions. She also denied receiving or being promised anything in exchange for her testimony and said her testimony was not for sale.

The defense was within its role in testing the credibility and possible bias of a prosecution witness. But asking a question is not proof that its premise is true. Tang's denial also does not end the inquiry by itself. The impeachment court must judge her answers, qualifications, consistency and the proper weight of her opinions.

5. THE CASE STILL TURNS ON THE DOCUMENTARY TRAIL

The prosecution has previously pointed to roughly P6.7 billion in reported bank transactions involving accounts it associates with Duterte and members of her family. That figure is politically explosive, but it must be handled carefully. A transaction total is not automatically the same as income, personal wealth or stolen money. Money may move more than once, flow between related accounts or come from lawful business and other legitimate sources.

To make the number meaningful, the prosecution must show whose accounts were involved, what period the transactions covered, whether the records are authentic, how the amounts were computed, and how they relate to Duterte's declared assets and lawful income. If it alleges that assets were held through companies or other people, it must prove the link rather than rely on association alone.

The defense, in turn, must do more than dismiss a figure as large or politically motivated if the underlying records are admitted and connected to Duterte. It will need to challenge the documents or provide a credible explanation for the transactions and any difference between the records and her declarations.