Feels like a long bow, but go on, I'm listening.
The sources I can find state:
"Then Minister for Home Affairs and Education, Chua Sian Chin said (Sing., Parliamentary Debates, vol. 37, col. 34 (27 May 1977)) - unless drug trafficking and drug addiction [are] checked, they [will] threaten our national security and viability. To do this, both punitive and preventive measures must be taken. The [Misuse of Drugs] Act was thus amended to provide enhanced penalties for traffickers, including mandatory death penalty for drug trafficking and manufacturing”.
So I'm wondering what was going in Singapore in the 70s.