Capital Punishment

Everyone has an inalienable human right to life, even those who commit murder; sentencing a person to death and executing them violates that right.

This is very similar to the 'value of life' argument, but approached from the perspective of human rights.

The counter-argument is that a person can, by their actions, forfeit human rights, and that murderers forfeit their right to life.

Another example will make this clear - a person forfeits their right to life if they start a murderous attack and the only way the victim can save their own life is by killing the attacker.

Execution of the innocent

The most common and most cogent argument against capital punishment is that sooner or later, innocent people will get killed, because of mistakes or flaws in the justice system.

Witnesses, (where they are part of the process), prosecutors and jurors can all make mistakes. When this is coupled with flaws in the system it is inevitable that innocent people will be convicted of crimes. Where capital punishment is used such mistakes cannot be put right.

Vengeance

The main argument that retribution is immoral is that it is just a sanitised form of vengeance. Scenes of howling mobs attacking prison vans containing those accused of murder on their way to and from court, or chanting aggressively outside prisons when an offender is being executed, suggest that vengeance remains a major ingredient in the public popularity of capital punishment.

But just retribution, designed to re-establish justice, can easily be distinguished from vengeance and vindictiveness.