The death penalty is to kill a criminal for a crime he committed. Previously worked most of the countries in this method of punishment, but today it is much less used in large scale. I personally do not think today's society is that the use of the death penalty, and I also believe that there are alternative punishments that can be used.
My main argument against the death penalty is that I have no right to kill another human being, regardless of the crime. I do not believe in the old religious adage "an eye for an eye." Modern societies must not resort to such cruel punishment.
Another argument against the death penalty is that people can be wrongly convicted and executed. If a man is in prison, he may be released if found not guilty later. If he is dead, there is nothing they can do. In the United Kingdom, has been sentenced by a group of alleged terrorists murder in Birmingham in 1970. It has been shown to be innocent after about 15 years and was released. If they had been executed, innocent people were killed.
There are alternatives available sanctions. Crimes can give a wrong judgment of prison life in prison with criminals imprisoned for the rest of their lives. Also a lot of horrible crimes are committed by people who are mentally ill. These people are not accountable for their actions, and can remain safely and permanently in the hospital safe. Yes, it costs more, but I think it is the duty of society to do so.
There are arguments in favor of the death penalty. Many people feel threatened stops serious crime and that criminals deserve no less. It's cheaper and keeps the prisons manageable. I can understand this point of view, but I can not agree with that.
So, in conclusion, I do not believe in the death penalty, as there is less barbaric alternatives available. We can choose to avoid these terrible mistakes and make modern society a more human.