The Philippine Senate formally elected Sherwin Gatchalian, an ally of President Ferdinand Marcos Jr., as Senate president during a special session, replacing Alan Peter Cayetano, an ally of Vice President Sara Duterte, The Philippine Star reported on June 17. All 13 senators present backed Gatchalian while Cayetano's bloc was absent, after Marcos called the special session to pass urgent bills, including an anti-political dynasty measure and an act on pending government appointments.

A second senatorial defection from the Duterte camp to the Marcos camp on June 17 gave the latter a 13-member bloc, sufficient to form a majority in the 24-seat chamber. Additionally, two Duterte-aligned senators are absent, with one under arrest for corruption and the other in hiding to avoid arrest under an International Criminal Court warrant. The Senate is scheduled to begin the vice president's impeachment trial on July 6, with control of Senate leadership having direct implications for the trial's scheduling and proceedings.