The governor of Illinois has signed a law that will ban the death penalty in the state, making it the sixteenth U.S. state to prohibit the ultimate punishment.

Governor Pat Quinn, a Democrat, also commuted the sentences of 15 death row inmates in the state to life without parole.

Fellow citizens, we cannot escape history, Quinn told reporters. “I think it’s the right, just thing to abolish the death penalty.”

Quinn signed the legislation surrounded by lawmakers and long-time opponents of capital punishment. Illinois has seen a number of people who were put on Death Row and later exonerated.

I have found no credible evidence that the death penalty has a deterrent effect on the crime of murder and that the enormous sums expended by the state in maintaining a death penalty system would be better spent on preventing crime and assisting victims' families in overcoming pain and grief, he wrote.

In 2000, former Illinois Governor George Ryan, a Republican declared a moratorium on executions after thirteen condemned prisoners were cleared since Illinois reinstated capital punishment in 1977.

Just before leaving office in January 2003, Ryan commuted the death sentences of 164 prisoners to life in prison. The next two governors, Rod Blagojevich and Quinn, maintained the moratorium.

For me, this was a difficult decision, quite literally the choice between life and death, Quinn wrote in a statement.

This was not a decision to be made lightly, or a decision that I came to without deep personal reflection. Since our experience has shown that there is no way to design a perfect death penalty system, free from the numerous flaws that can lead to wrongful convictions or discriminatory treatment, I have concluded that the proper course of action is to abolish it. With our broken system, we cannot ensure justice is achieved in every case.

Quinn added: for the same reason, I have also decided to commute the sentences of those currently on death row to natural life imprisonment, without the possibility of parole or release.”

In recent years, New York, New Jersey and New Mexico, have all abolished the death penalty.

“There are no words in the English language, or any language, to ease your pain,” he said of the relatives of murder victims’ who opposed the move.

“I want to tell them, it’s impossible, I’m sure, to ever be healed. But we want to tell all of the family members, the family of Illinois…we want to be with you. You’re not alone in your grief.”

The death penalty ban will take effect July 1.

According to Amnesty International, almost 75 percent of all countries in the world have either abolished the death penalty or haven't executed anybody for at least ten years.

However eight of the 10 most populous countries (including China, India, the U.S. and Indonesia leading the way) allow capital punishment.