Capital punishment, or the death penalty, is the judicially-sanctioned killing of a person for a criminal offense. Typically, this is carried out only for the most serious offenses such as murder, though different states have different ideas of seriousness: some Muslim states have capital punishment for apostasy or homosexual behaviour, for example. The number of countries imposing the death penalty has decreased significantly, with civil liberties and human rights treaties, including the European Convention on Human Rights, forbidding the use of the penalty across all member states of the European Union, while other countries, including the United States of America, Iran, Iraq, Japan, China, Saudi Arabia and Taiwan, retain its use. Within the United States of America, the federal government and 36 states permit the death penalty, with the State of Texas being a notable example for the large number of executions it carries out.
In the United States of America, the method of execution is primarily that of lethal injection, which is seen as a more humane alternative to the use of the electric chair, the gas chamber, shooting by an individual executioner or firing squad and hanging. On a number of occasions, it was quite difficult to insert the lethal injection tubing into the condemned, and there is not total medical certainty that the individual becomes unconscious with the first of the three drugs used.
Supporters of the death penalty argue that it is effective in deterring criminals, and that it gives the families of victims a sense of closure. Many draw on the Biblical principle of an eye for an eye, and some argue that it is fairer on the public purse to kill a murderer than pay for his lifelong imprisonment. The death penalty is also seen by some as the best guarantee of public safety, because a convicted murderer can never be given parole or escape from prison.
Opponents of the death penalty point towards statistical evidence demonstrating that the death penalty has no deterrent effect, noting that murder is usually committed without thought as to the consequences. Many point to the fact that countries like the United Kingdom, which abolished the death penalty, did not see a long term change in the murder rate after abolition. Opponents also argue that the principle of retributive justice is barbaric, and point to opposition by a large number of religious groups. Many death penalty abolitionists and opponents also argue that death penalty systems are often racist, executing disproportionate numbers of prisoners from minority groups. They also point to the accidental executions of innocents, arguing that no system of capital punishment can guarantee that innocent people will never be put to death. In support of this, they point to numerous executed prisoners who have since been pardoned through the use of DNA evidence and through posthumous appeal (e.g. Derek Bentley).