Harsh Punishments -- really effective?

Of course, most will argue that harsh punishments are effective as they act as a deterrence. But sometimes, it can backfire, as in the case below. While the court in Bangladesh has chosen to go by the book and 'make the punishment fit the crime', many may have done otherwise in the light of the highly charged and volatile political climate. Consider Singapore's controversial reduction of the strokes of the caning from 6 to 4 for the Michael Fay incident some decades back....Consider also this: If Yingluck managed to catch Suthep (the Opposition Leader of the current protests in Thailand), do you think she will give him the maximum penalty under the law in order to make an example of him so that no others will dare to protest against her govt in the future (i.e. deterrence)? And what about the Indonesian govt letting that religious leader (forgot his name) off with a lighter sentence despite his role in masterminding the Bali Bombing some years back? And does the Italian courts dare to touch the mafia? But then again, Kim Jong Un (leader of North Korea) dares to do what these others did not. Only a few days ago, he executed his uncle for daring to challenge him in an alleged power grab. So what makes for the difference?

Sample Qns:
1. How effective are harsh punishments in dealing with crime?
2. To what extent is it possible to make the punishment fit the crime? (Cambridge 2013)