Although this argument may seem unjust or immoral, the death penalty is a necessary way to enforce justice in our modern world. Crimes such as murder or terrorism aren't ones that can be repaid with a meagre jail sentence. In Australia, the average 'life sentence' lasts 25 years on parole. in America, some murderers can be let out of prison as early as 15 years after the sentence. If you've killed someone, that's a life they will never get back. 25 years is merely a third of the average life span, 15 is a fifth. If a 20 year old were to murder someone, it is possible they would be out of jail before they are 50. Justice is not being served in the eyes of the law, despite the fact that a life sentence is supposed to last the rest of someone's life.