One of the critical chinks in Singapore's defensive chain-mail is NOT a military one, but one of sustainability. Singapore has ZERO ability to grow or produce enough food to feed it's population (simply no arable land available), it relies totally on external exports. Rice, dairy, meat, cereals all have to be imported by ship or transferred across the causeway from Malaysia. If, say for arguments sake, Malaysia closed the causeway and threatened to mine the approaches to Singapore then, strong military or not, the country would face tough times. The 900, 000 odd expats would leave for one, which would have a massive impact upon the economy. Singapore's fiscal reserves are extremely robust and will be able to provide a buffer to any financial crunch, however the population can't eat money! Singapore's only choice under the circumstances would be to move North and seize land for agricultural production, and / or expand it's MCM/ASW capabilities to the point where it can guarantee clear sea-lanes.