Actually from a right wing point of view ISA and ISD is a good tool to deal with terrorist and organised crime to keep society safe. The problem with Singapore is that detention without trial is for an indefinite period. I think there is a review once every 2 years but the review is just window dressing.
In HK, suspects can be detained only for 48 hrs. And is not used against political opponents unlike in spore where ISA is used on political opponents. I have not seen the ISA used on criminals but maybe Mas Selamat. However in spore ISA is also used to scare the populace, like Mas Selamat, to show the world spore is doing something.
That is one of the problems with ISA in singapore..we are still a one Party.,,,oh no,,a one Familee dictatorship.