The Philippine Senate convened on Monday as an impeachment court for Vice-President Sara Duterte-Carpio, even as a fresh battle for control of the chamber threatens to shape the direction of her trial and the fallout from the crimes-against-humanity case against her father, former president Rodrigo Duterte, in The Hague.

Duterte-Carpio was impeached by the House of Representatives last week on allegations including corruption, betrayal of public trust and culpable violations of the constitution after a bitter falling-out between the Duterte and Marcos political dynasties, whose alliance swept President Ferdinand Marcos Jnr and the vice-president to power in 2022.

The Senate trial could determine not only whether Duterte-Carpio is removed from office, but also whether she is barred from holding public office – a potentially decisive blow to her 2028 presidential run.

The sitting came after days of turmoil in the Senate, where a leadership change, a dramatic stand-off over Senator Ronald “Bato” dela Rosa and reports of another move to replace Senate President Alan Peter Cayetano have raised the stakes of Duterte-Carpio’s impeachment trial.

As the Senate leader is expected to preside over the impeachment proceedings, the fight over Cayetano’s leadership is central to how quickly the trial moves and how the chamber handles politically sensitive issues involving the Dutertes and their allies.