The arrest of Philippine Senator Jinggoy Estrada has deepened a stand-off in the Senate, leaving the chamber split between two 11-member blocs and raising the risk of a wider political crisis, analysts told This Week in Asia.They warned the stalemate could stall legislation, delay military appointments and complicate Vice-President Sara Duterte-Carpio’s impeachment trial, leaving the Senate’s basic ability to do business hostage to a factional power struggle.Estrada, chairman of the Senate defence committee, was arrested on Monday on a non-bailable corruption charge, further weakening the bloc that installed Alan Peter Cayetano as Senate president last month after a leadership challenge that ousted Vicente “Tito” Sotto III.His arrest came after Senator Ronald “Bato” Dela Rosa, a close Duterte ally and former police chief, went into hiding after the International Criminal Court (ICC) issued an arrest warrant over alleged crimes against humanity linked to Duterte’s drug war.01:01Philippine lawmaker charged with corruption surrenders in connection with flood-control scandalWith both Estrada and Dela Rosa unable to attend Senate activities, Cayetano’s 13-member “majority bloc” has been reduced to 11 senators – the same number as the “minority bloc”.“This [kind of number stalemate] has never happened before,” said University of the Philippines political science professor Dr Jean Franco.