The Supreme Court (SC) on Wednesday dismissed a petition seeking to compel the Senate to immediately convene as an impeachment court to try the charges against Vice President Sara Duterte.

In a 14-0-1 decision penned by Associate Justice Rodil Zalameda, the SC rejected the petition for mandamus filed by Catalino Aldea Generillo Jr., which asked the High Court to compel the Senate to act on the impeachment case. 

It ruled that mandamus was not the proper remedy, stressing that it applies only when there is a clear and ministerial duty to act.

The SC emphasized that the Senate, part of a coequal branch of government, cannot be compelled through mandamus in the performance of its constitutional functions, except in cases involving grave abuse of discretion.

However, “in the interest of equity,” the SC treated the petition as one for certiorari and determined whether the Senate acted with grave abuse of discretion in not immediately convening as an impeachment court during a session break.

The High Court found none.

“Contrary to the petitioner’s claim, the SC found that the Senate acted on the impeachment complaint in a timely manner,” SC said.

It ruled that the Senate acted within a reasonable period and that the Constitution does not prescribe a fixed deadline for the Senate to begin an impeachment trial. 

“While the Constitution requires the House of Representatives to act within a certain number of session days on an impeachment complaint, it does not specify a fixed timeframe for the Senate to start an impeachment trial. It simply provides that the trial ‘shall forthwith proceed,’ leaving the timing to the Senate’s discretion,” the High Court explained. 

While Article XI, Section 3(4) of the Constitution requires that an impeachment trial “shall forthwith proceed,” the SC clarified that “forthwith” means within a reasonable time, depending on the circumstances, and allows the Senate time to make necessary preparations.

The SC also noted that the petition had become moot. 

It pointed out that the Senate had already begun impeachment preparations and that the Articles of Impeachment against Vice President Duterte had been nullified by earlier SC rulings in Duterte v. House of Representatives (July 25, 2025 Decision and 28 January 2026 Resolution). 

With no valid Articles of Impeachment remaining, there was no longer a case requiring the Senate to convene as an impeachment court.

“A case is moot when subsequent events remove any issues, making court rulings unnecessary,” the Court said, adding that there was no longer a legal basis to grant the relief sought.

Associate Justice Alfredo Benjamin Caguioa took no part in the case.