There are many protections in place within the confines of what is considered the judicial branch of government whose guidelines have been primarily set forth by legislature. The dual court system in the United States and opportunity for appealing up to the Supreme Court level as well as trial by a jury of one's peers conveys some of these. When a jury is selected, a group of questions is posed to potential jurors in order to eliminate any biased parties. The initial trial takes place in the state where the crime was said to have taken place. However, people can lie. Perhaps a potential juror has some sort of personal vendetta against a race or lifestyle and makes their way onto the jury. This juror has the chance to sway others votes and put an innocent person behind bars based on skin colour or sexual preference.
It is difficult to determine an alternative method for selecting jurors who take place in the sentencing process. Even if they are not predisposed to information regarding those charged, questions regarding discrimination may result in falsifications just to become a member of the jury. We can set even stricter crime scene rules and regulations, but there is always a potential for error. Judgement is not something that will ever be made by computers; it involves the human thought process and, therefore, will never be foolproof.