when crimes are premeditated the primary deterrent is not the punishment, its the expectation of being caught. If the expectation is high, then even relatively minor punishments will deter.

obviously if you are a corruption fuelled third world country, where the police, judges and politicians prostitute themselves for coin.... then without dealing with that issue first.... the expectation criminals will have of being caught and punished is very low.... rendering the the death sentence rather poor deterrent.

The article that kingwilly posted (Bali Executions) earlier today make some rather interesting points, the Indonesian president personally collates the death lists and he's got a serious hard on for disproportionately killing foreigners at 87% of those killed. which has the advantage of not annoying any local voters at home.

its also quite interesting that the info foreign ministry is quite proud of their success in interfering with foreign judicial systems successfully commuting over 160 death sentence given to Indonesians in foreign countries.

Another thing to consider look at the countries that do execute people, they all have governments that have general lack of interest in the well being of their own citizenry and the value of their life. And yes I do include the US, the current bomb fires are a result of their police being over enthusiastic with the application of violence... hell they even taiser people for fighting drones over volcanos!
The death sentence teaches governments bad habits that ultimate affect the greater part of the counties population beyond drug smugglers.