With Seth Williams' decision not to seek a third term as district attorney, Philadelphia now has a chance to join the rest of the Northeast in moving forward without the death penalty.

Our next district attorney should be smart on fighting crime, and not waste valuable resources by seeking a fiscally irresponsible, legally impractical, and morally indefensible punishment. The death penalty is an expensive and anachronistic relic, and we are better off without it.

This is hardly a bold suggestion. In reality, Pennsylvania has not had a working death penalty in decades. The last involuntary execution - one in which the condemned was not a willing participant - occurred in 1962. Pennsylvania has only executed three men in the past 55 years, all of whom gave up their appeals and sought their own deaths at the hands of the state. We have not executed a single person this century.

Nor are juries enamored of the punishment. Death sentences have dropped precipitously since the 1990s, when the state averaged well more than 10 per year. Over the past five years, that average has dropped to three - meaning that fewer than half of one percent of murders now end in the ultimate punishment. In 2016 there was a single death sentence in the state. And Pennsylvania is not alone in this trend; the country is now at all-time lows for executions and death sentences.

There is no single reason for the steep decline of capital punishment. The advent of DNA evidence has demonstrated that innocent people have sometimes been convicted of the most serious crimes. The recent exoneration of Anthony Wright after 25 years in prison is a case in point. The jury forewoman expressed frustration that the case had even been retried. "I'm angry," she said. "The [DNA test] was there that he did not commit this crime. The city should never have brought this case."

What went unmentioned is that Philadelphia prosecutors sought the death penalty against Wright at his first trial 22 years earlier. Had they succeeded, he would not have been around to enjoy his belated freedom.

DNA has revealed such mistakes, and we now know a lot more about the cause of them as well. The science behind wrongful identifications and false confessions can no longer be ignored, and cases that appeared rock solid are now properly viewed as flawed. Using the threat of the death penalty as leverage to coerce a guilty plea from an accused fearful of execution is not only an unconstitutional use of the punishment, but is likely to lead to a wrongful conviction. And prosecutorial misconduct through the withholding of important police paperwork - a reality in an unconscionable number of Philadelphia murder reversals - is a culture that must be condemned rather than rationalized and excused in a progressive District Attorney's Office.

In addition, the city's continued refusal to properly train and resource the defense has cost us dearly. Philadelphia leads the country by far in death sentences reversed, a result that is unfair to families of victims and defendants alike and has exacerbated the pain of violent crime in an unnecessary way. The financial cost has also been extreme.

Not long ago, the Rand Corporation determined that the haphazard representation by undertrained and underresourced court-appointed counsel in homicide cases in Philadelphia actually cost the taxpayers more than $200 million for excess incarceration from 1994-2005. A fair criminal justice system cannot be cheap - and the Rand study teaches us that a penny-wise-pound-foolish approach is the surest recipe for injustice.

Gov. Wolf bravely faced these issues when he first took office, declaring a moratorium on executions until he saw the implementation of real reforms. Unfortunately, the ink was not dry on the governor's proclamation when Seth Williams immediately, and thoughtlessly, appealed the decision to the Pennsylvania Supreme Court. He lost unanimously.

A bipartisan committee continues to study capital punishment in Pennsylvania, and one conclusion is virtually certain: If we want a death penalty that meets even the bare minimum requirements for fairness, it will be expensive.

So, given the possibility of mistakes, the consistently outrageous error rate, the absurd cost, and the complete randomness and impracticality of the punishment, why has the Philadelphia district attorney been such an outlier in continuing to press for death sentence after death sentence?

We have been sold a bill of goods by politicians who talk tough for their own benefit, but we can no longer afford this flawed policy. The death penalty has not worked and is not working, and we can no longer afford to waste money so that self-aggrandizing politicians can promote themselves.

The city's next district attorney must end the death penalty in Philadelphia.

Marc Bookman is director of the Atlantic Center for Capital Representation in Philadelphia. mbookman@atlanticcenter.org