Capital punishment is the least of the justice system's problems.

Pennsylvania has carried out only three executions since it reinstated the death penalty in 1976. All three were of men who volunteered to be executed.

The state's dormant death penalty contrasts starkly with the 236 executions presided over by Texas Gov. Rick Perry, and also with the death chamber at the Georgia Diagnostic and Classification Center in Butts County, where the execution of convicted killer Troy Davis caused a media frenzy last month.

By midnight on Sept. 21, despite the notoriety, Davis was dead. So was his victim, Michael Allen MacPhail, along with about 675,000 others who have been murdered in this country since the death penalty was reinstated.

Only a tiny fraction of those who kill ultimately pay with their lives. Since 1976, 1,271 men and women have been executed in the United States. More important, a much greater number of those responsible for murder have never even been arrested. A killer is 200 times more likely to get away with murder than to be executed for it.

That number has not improved. In 1961, 91 percent of killings were "cleared" - the term used by police to indicate an arrest has been made. In 2010, only 64 percent were. That means the killers of more than 5,000 people in 2010 alone could be at large, including the killers of more than 150 in Pennsylvania.

Where's the outrage over that? Why haven't the media lamented those 5,000 families who lost a loved one by the hand of someone who has never been identified?

The sorrow that envelops the family of a murder victim, particularly when the murder is unsolved, permeates entire communities. Unsolved homicides also hurt public confidence in the police and diminish police productivity, according to the Police Executive Research Forum. And, to the extent that offenders literally "get away with murder" and the public knows it, deterrence becomes more difficult.

Officer MacPhail's murder was solved, but his killer became the subject of considerable attention and speculation. Nevertheless, death penalty opponents cannot point to a single case in which an innocent person has been executed in the past 35 years - although they have certainly tried. One of their favorite cases was that of Roger Coleman, who was convicted of the rape and murder of his sister-in-law in Virginia. Before he became a suspect, Coleman had the audacity to serve as one of the victim's pallbearers.

Coleman's protestations of innocence became a cause célèbre, landing him on the cover of Time magazine and gaining the badly misplaced trust of many in the anti-death penalty movement. As he was strapped into the electric chair in May 1992, he said, "An innocent man is going to be murdered tonight." Sixteen years after his execution, the governor of Virginia ordered posthumous DNA testing that confirmed Coleman's guilt.

The U.S. Supreme Court ordered an evidentiary hearing in the Troy Davis case in June 2010. Two months later, a U.S. District Court in Georgia ruled: "Ultimately, while Mr. Davis's new evidence casts some additional, minimal doubt on his conviction, it is largely smoke and mirrors. . . . After careful consideration, the Court finds that Mr. Davis has failed to make a showing of actual innocence. ..." Davis was finally executed 22 years after the killing of MacPhail.

An estimated 230,000 killings remain unsolved since the reinstatement of capital punishment. Yet more time, attention, and resources continue to be focused on the rare challenge to an execution that somehow captures the morbid curiosity of the public. Whether a condemned killer lives or dies strikes me as far less important than the literally thousands of killers who are walking America's streets.