Former Supreme Court associate justice Adolfo Azcuna said Thursday that the high court overstepped Congress by imposing a new set of rules on how an impeachment case should be initiated — a prerogative exclusively reserved to the House of Representatives.

Azcuna, a member of the Constitutional Commission that crafted the 1987 Constitution, argued that the Supreme Court’s role is limited to interpreting constitutional provisions that are already specified in the rules, including those governing impeachment.

However, in the case of the impeachment of Vice President Sara Duterte, Azcuna noted that the Court introduced seven new requirements, including ensuring that members of the House are given ample time to review the complaint before signing it, and that the complaint is properly circulated — provisions not explicitly mandated by the Constitution.

“In this present case, however, mind you, the Supreme Court went beyond mere interpretation and proceeded to impose its new set of rules to be followed in impeachment to be followed by the House. I believe that is beyond its power of interpretation,” Azcuna said in an interview.

He cited the precedent set in Francisco v. House of Representatives, where the Supreme Court did not introduce rules to be followed by Congress but merely interpreted the word “initiation” as outlined in the Constitution. Under that jurisprudence, the Court ruled that initiation “takes place by the act of filing of the impeachment complaint and referral to the House Committee on Justice.”

In impeaching Duterte on 5 February, the House used the second constitutional mode: garnering the required one-third vote of all House members to bypass the committee process and send the complaint directly to the Senate for trial.

However, the Supreme Court’s unanimous ruling declared that the earlier inaction of the House on the first three complaints — placing them in the archives — constituted termination and dismissal, thus triggering the one-year bar on filing another impeachment.

The Court also ruled that Duterte was denied due process when the House expedited the process by transmitting the articles to the Senate without allowing her to answer the allegations — a requirement not found in the Constitution, according to the signatories of the articles.

According to Azcuna, “the House is not obliged to observe these rules,” asserting that due process applies only during the Senate trial stage. He also criticized the new requirement from the Court that lawmakers fully understand the contents of the complaint before signing, calling it a “comprehension test” and an “insult to the minds of legislators.”

“That is presumed; you do not have to prove that you understood the articles. That’s what the Supreme Court would least require of our legislators in future impeachment cases. To mind you, this is overstepping the bounds of the Constitution,” Azcuna said.

In a Friday briefing, Manila Rep. Joel Chua — one of the lawmakers assigned to prosecute Duterte — shared the same concerns. He said that setting new parameters for the House to follow goes beyond the Supreme Court’s power and intrudes on a co-equal branch of government.

He warned that the added requirements would make it more difficult for the House to initiate impeachment proceedings and hold high-ranking officials accountable.

“With all due respect to the Supreme Court, they made the steps more difficult. Actually, it is stated in our Constitution that Congress shall promulgate its [impeachment rules]… But in this new ruling by our Supreme Court, where they added some parameters or steps to elevate an impeachment, it will be more difficult,” Chua said partly in Filipino.

To recall, Duterte was hit with three impeachment complaints in under two weeks in December 2024, but was only officially impeached on 5 February after the fourth complaint was signed and endorsed by 215 House members — more than double the one-third threshold. The complaint was transmitted directly to the Senate, which later archived the articles following the Supreme Court ruling. The Senate voted 19-4-1 to follow the decision.