Former Senate President Franklin Drilon said the impeachment cases against Vice President Sara Duterte could test the limits of the Supreme Court’s (sc) authority, particularly on whether it can intervene in congressional proceedings on grounds of grave abuse of discretion.

Drilon said any ruling by the high court on petitions seeking to halt the impeachment process would serve as a benchmark for judicial power under the Constitution, noting that impeachment is primarily a political process entrusted to Congress.

“The intervention of the Supreme Court in the impeachment of Vice President Sara Duterte presents an interesting study on the limits of the court’s intervention on what is known or considered as a political question,” Drilon said during the launch of his memoir at the University of the Philippines College of Law on Sunday.

He said the case could clarify how far the judiciary may go in reviewing impeachment proceedings, particularly in determining whether lawmakers committed grave abuse of discretion.

“To what extent the Supreme Court will invoke its constitutional power to correct grave abuse of discretion in the political process involving the impeachment of Vice President Duterte will be an interesting study for all of us,” he said.

Several petitions have been filed before the SC seeking to stop the proceedings, citing alleged procedural lapses and constitutional violations by the House of Representatives and its justice committee.

Interventions

One petition, led by lawyer Israelito Torreon, argued that the House panel exceeded its mandate by conducting extensive evidence-gathering beyond determining the sufficiency of complaints, describing the process as a “fishing expedition.”

In a separate petition, Duterte asked the court to issue a temporary restraining order, alleging violations of due process and the one-year bar rule on impeachment complaints. She also said the hearings resembled a trial, a function reserved for the Senate.

Both petitions seek to declare the House committee’s actions unconstitutional and suspend proceedings while under review. Another group of lawyers, academicians, and Muslim leaders has also sought to intervene.

Retired SC Justice Adolfo Azcuna earlier warned that the House may be overstepping its role by turning preliminary proceedings into a full-blown trial.

“They should not be the ones to expound on the discrepancies… that will be preempting the role of the Senate,” Azcuna said.

He added that while the House has subpoena powers, these should be exercised sparingly to avoid encroaching on the Senate’s jurisdiction.