History of Singapore
During World War 2, Singapore was conquered and occupied by the Japanese Empire from 1942 to 1945. When the war ended, Singapore reverted to British control, with increasing levels of self-government being granted, culminating in Singapore's merger with the Federation of Malaya to form Malaysia in 1963. However, social unrest and disputes between Singapore's ruling People's Action Party and Malaysia's Alliance Party resulted in Singapore's expulsion from Malaysia. Singapore became an independent republic on 9 August 1965.
History of the Republic of Singapore
The other major issue brought up around this time was national defence. Following independence, the British were still defending Singapore, but had announced they would be withdrawing by 1971, due to pressures at home and military commitments elsewhere in the world. This caused considerable alarm locally, particularly among those who remembered the Japanese occupation during World War II.