Posted by Ray Long at 11:59 a.m.; updated at 12:05 p.m.

SPRINGFIELD — Gov. Pat Quinn today signed into law a historic ban on the death penalty in Illinois and commuted the sentences of 15 death row inmates to life without parole.

Quinn signed the legislation in his Capitol office surrounded by longtime opponents of capital punishment in a state where flaws in the process led to the exoneration of numerous people sentenced to death.

"For me, this was a difficult decision, quite literally the choice between life and death," Quinn wrote in his signing 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," Quinn wrote. "With our broken system, we cannot ensure justice is achieved in every case."

"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," the governor wrote.

A small group of lawmakers also was on hand, including lead sponsors Rep. Karen Yarbrough, D-Maywood, and Sen. Kwame Raoul, D-Chicago. Senate President John Cullerton, D-Chicago, and House Majority Leader Barbara Flynn Currie, D-Chicago also attended. Lt. Gov. Sheila Simon, who lobbied Quinn to sign the ban, was there.

The ban comes about 11 years after then-Gov. George Ryan declared a moratorium on executions after 13 condemned inmates were cleared since Illinois reinstated capital punishment in 1977. Ryan, a Republican, cited a Tribune investigative series that examined each of the state's nearly 300 capital cases and exposed how bias, error and incompetence undermined many of them.

Since then, Illinois approved reforms to the capital punishment system, including taping interrogations under a proposal forged by President Barack Obama when he served in the Illinois Senate. Only two days before leaving office in January 2003, Ryan commuted the death sentences of 164 prisoners to life in prison. Quinn and his predecessor, Rod Blagojevich, kept the moratorium in place.

In 1972, the U.S. Supreme Court struck down death penalty statutes in 40 states, including Illinois. Five years later, Illinois reinstated capital punishment, and it has been among the 35 states that currently allow executions. Illinois could join New York, New Jersey and New Mexico, all of which have done away with the death penalty in the last three years.

The death penalty ban would take effect July 1.

Quinn did not have to immediately act on the 15 death row inmates, but chose to commute their sentences to life in prison.

One of them is Brian Dugan, sentenced to death for the 1983 rape and murder of 10-year-old Jeanine Nicarico, of Naperville. Dugan had been serving two life sentences for two other rape-murder cases, but his death sentence brought a major chapter of a long-running, controversial case to a close. Rolando Cruz and Alejandro Hernandez — two of three men originally charged with the girl's murder — served years on death row before they were cleared.

As Quinn campaigned for governor last fall, he held firm to the moratorium as a way to see how well the reforms are working. The governor also said he supported the death penalty for the worst crimes.

Quinn made his decision after an intense lobbying effort from those on both sides of the issue.

Cook County State's Attorney Anita Alvarez, Illinois Attorney General Lisa Madigan and other prosecutors urged Quinn to veto the ban and take a hard-line stance to keep the death penalty.

The governor also heard from anti-death-penalty luminaries including South African Archbishop Desmond Tutu and Sister Helen Prejean, a New Orleans nun whose time spent with a condemned inmate became the basis for the movie "Dead Man Walking."

Family members of murder victims also made emotional pleas. Among them was Cindy McNamara, whose daughter, Shannon, was murdered in 2001 while attending Eastern Illinois University.

Shannon McNamara was asleep in her locked off-campus apartment when she was raped, strangled, beaten and stabbed. Her body was left in the living room. A washcloth was stuffed in her mouth.

Former EIU student Anthony Mertz was convicted, becoming the first person sent to death row after Ryan emptied it.

"We have the death penalty for a reason," Cindy McNamara wrote in a letter to Quinn. "This is the reason!"

The Tribune examination found at least 46 inmates sent to death row in cases where prosecutors used jailhouse informants to convict or condemn the defendants. The investigation also found at least 33 death row inmates had been represented at trial by an attorney who had been disbarred or suspended; at least 35 African-American inmates on death row who had been convicted or condemned by an all-white jury; and about half of the nearly 300 capital cases had been reversed for a new trial or sentencing hearing.