Lee Kuan Yew and his PAP cabinet would have been arrested, and emergency rule would be declared by the federal government over the state of Singapore. In May 1965, Lee had formed the Malaysian Solidarity Convention with other parties to advocate for a multiracial Malaysia, and he was already posing an active threat to the power of the Alliance government in Kuala Lumpur.
Arresting Lee and his government was the demand of the hardliners in UMNO. Tunku Abdul Rahman feared things would turn bloody and that the UMNO extremists, including Mahathir Mohammad would overthrow him as Prime Minister, so he proposed that Singapore be expelled from the Federation of Malaysia.
Nevertheless, the 1969 race riots would be the moment when Tunku was basically removed from power by UMNO extremists to an emergency government.