West Malaysia went to the polls on 10 May, while Sabah was scheduled to vote on 25 May and Sarawak on 7 June. The Alliance won 10 seats in Sabah on nomination day being unopposed in some constituencies, so after the West Malaysian elections they were assured of a clear majority of 76 out of a total of 144 parliamentary seats. Tun Mustapha Datu Harun’s United Sabah National Organisation (Usno) won 10 out of 16 seats unopposed for the Alliance on nomination day.
The opposition parties’ gain at state level was more shocking to the Alliance Party which not only continued to lose to PAS in Kelantan, but also to political infant Gerakan in Penang. No party commanded an absolute majority in two other states. The Alliance held only 14 out of 24 seats in Selangor and 19 out of 40 in Perak.
Very interestingly, the attrition of Malay support was much higher than that of the non-Malays. Malay opposition parties’ vote shares in the peninsula increased drastically from about 15% in 1964 to 25% in 1969 while the support for non-Malay opposition parties remained roughly the same at 26% in both elections. Thanks to the electoral system, however, PAS seats increased from nine to 12 seats only while the non-Malay opposition parties from eight to 25.
Gerakan and DAP held a victory rally in Kuala Lumpur on 12 May, but the rally turned rowdy, with party members shouting racial epithets at Malay bystanders. UMNO retaliated with its own rally on 13 May, which soon broke out into full-scale rioting, which subsequently became known as the 13 May Incident.