The criminal justice system is fair
Australia's criminal justice system is largely fair, but that certainly can’t be said of many of the countries using the death penalty. We know that the death penalty is applied overwhelmingly to the working class, ethnic minorities and other marginalised groups. This happens not because people in these categories are more prone to crime, but because they have less access to legal resources.
Ask any criminal lawyer whether or not the amount of legal resources available on a particular case makes a difference and they will give you a deadpan ‘yes’. Legal support might not get the verdict is changed, but mitigating circumstances can be presented, alternate arguments explored and evidence double-checked. All of this makes a difference to whether a death sentence is handed down.
Many justice systems are stacked against the person charged with the crime. Siti Zainab is an Indonesian national on death row in Saudi Arabia. Siti was a domestic worker who, after horrific treatment at the hands of her employer, allegedly killed a member of the household. Domestic workers are often unable to escape their employers treatment in the Gulf and Siti reportedly suffers from a mental illness.
Regardless of the country, a fair criminal justice system does not mean an infallible one - errors can and do occur. Troy Davis was executed in Georgia, USA after seven of nine key witnesses changed their testimony, some going so far as to argue for Troy's innocence.
We can't give back a life once it is taken, and for one I would prefer a cautious approach to even the slightest possibility of taking an innocent person's life.