Supporters of the death penalty argued that death penalty is morally justified when applied in murder especially with aggravating elements such as multiple homicide, child murder, torture murder and mass killing such as [terrorism], massacre, or genocide. Some even argue that not applying death penalty in latter cases is patently unjust. This argument is strongly defended by New York law professor Robert Blecker , who says that the punishment must be painful in proportion to the crime. It would be unfair that those who have committed these horrible crimes stay alive, even incarcerated. Abolitionists argue that retribution is simply revenge and cannot be condoned. Others while accepting retribution as an element of criminal justice nonetheless argue that life without parole is a sufficient substitute. Human rights
Abolitionists believe capital punishment is the worst violation of human rights, because the right to life is the most important, and judicial execution violates it without necessity and inflicts to the condemned a psychological torture. Albert Camus wrote in a 1956 book called "Reflections on the Guillotine, Resistance, Rebellion & Death": An execution is not simply death. It is just as different from the privation of life as a concentration camp is from prison. [...] For there to be an equivalency, the death penalty would have to punish a criminal who had warned his victim of the date at which he would inflict a horrible death on him and who, from that moment onward, had confined him at his mercy for months. Such a monster is not encountered in private life.  This view contradicts classic natural rights doctrine, which stresses that the right to life can be forfeited by grave misbehavior. Practical arguments
Main article: Wrongful execution
Capital punishment is often opposed on the grounds that innocent people will inevitably be executed. Supporters of capital punishment object that these lives have to be weighed against the far more numerous innocent people whose lives can be saved if the murderers are deterred by the prospect of being executed. Between 1973 and 2005, 123 people in 25 states were released from death row when new evidence of their innocence emerged. However, statistics likely understate the actual problem of wrongful convictions because once an execution has occurred there is often insufficient motivation and finance to keep a case open, and it becomes unlikely at that point that the miscarriage of justice will ever be exposed. Another issue is the quality of the defense in a case where the accused has a public defender. The competence of the defense attorney "is a better predictor of whether or not someone will be sentenced to death than the facts of the crime". Also, improper procedure may result in unfair executions. For example, Amnesty International argues that, in Singapore, "the Misuse of Drugs Act contains a series of presumptions which shift the burden of proof from the prosecution to the accused. This conflicts with the universally guaranteed right to be presumed innocent until proven guilty". This refers to a situation when someone is being caught with drugs. In this situation, in almost any jurisdiction, the prosecution has a prima facie case. Racial and gender factors in the United States
African Americans, though they currently make up only 12 percent of the general population, have made up 41 percent of death row inmates and 34 percent of those actually executed since 1976. According to Craig Rice, a black member of the Maryland state legislature: "The question is, are more people of color on death row because the system puts them there or are they committing more crimes because of unequal access to education and opportunity? The way I was raised, it was always to be held accountable for your actions." As of 2010, women account for only 1.7% (55 people) of inmates on death row, with men...