I am against the death penalty. In short, you can never be 100% sure that someone is guilty. Even in cases where the accused has confessed the crime. There are plenty of cases where people have confessed to thing that didn't do.
This in itself is reason enough to abolish the death penalty. A human life is sacred, you can not take one when you can not be sure that it is justified. It is a fact that having the death penalty leads to innocent people being killed by the state. That is unacceptable. It is not an argument that other people have killed people and should be killed for it, you can not have a system that risks killing innocent people.
There are many other arguments against the death penalty, they are all inferior to this point.
On the other hand, there are no good arguments for the death penalty. Protecting the general public is accomplished by life in prison (yes, people can escape prison, but then they can also escape from death row?). The feelings of the relatives is possibly the strongest argument for the death penalty, but it is also flawed. I do acknowledge that people who have horrible crimes committed against their loved ones will have a strong need for revenge in many cases, but fulfilling this wish should not be the goal of the justice system. Justice has to be cold and emotionless, if not it can not be fair. While I certainly can sympathize and even applaud people who take their revenge personally, I can't get behind the idea of administrating revenge institutionally.
