The Philippine Senate failed to open its June 1 session after recent events reduced the 13-member majority bloc to 11 senators, prompting the bloc — which also includes the Senate president — to skip the session rather than risk losing control of the floor, Bloomberg reported the next day. The resulting paralysis delayed regular Senate business and led to the cancellation of a visit to the Senate by Vietnam's leader To Lam, who was in Manila and upgraded bilateral ties with Philippine President Ferdinand Marcos Jr. the day prior.

Sen. Jinggoy Estrada was arrested on June 1 on suspicion of embezzlement, and Sen. Ronald "Bato" dela Rosa's has been absent since May 14 in light of an International Criminal Court warrant for his arrest. Estrada's arrest matters because he was part of a narrow bloc of senators that ousted Marcos-aligned senate leadership and installed Duterte-aligned replacements on May 11, the same day the House passed the impeachment case to the Senate. His detention, combined with dela Rosa's absence, has turned the pro-Duterte bloc's nominal 13-11 majority into an effective 11-11 split with rival pro-Marcos senators.