Manila, Sept. 16 -- Senator-judges must personally engage with the evidence in an impeachment trial before exercising the power to decide an official's fate, retired chief justice Artemio Panganiban told the Senate impeachment court Wednesday.

Panganiban said the constitutional duty of senator-judges requires more than simply being counted as members of the chamber, stressing that "active participation and independent evaluation of the evidence are essential" to meaningful adjudication.

He said determining truth entails studying documents, hearing witnesses, and observing their demeanor on the stand - including their body language, tone of voice, and spontaneity in answering questions.

Fairness, meanwhile, requires giving both sides th...