For 22 years, Nick Yarris sat on death row in Pennsylvania for the rape and murder of a Delaware County woman.

Yarris would have died in prison if not for a DNA test that showed he wasn't the rapist or killer.

His conviction was overturned in 2003, and last week he received the final installment of a $4 million settlement stemming from a malicious-prosecution lawsuit he brought against prosecutors in Delaware County.

Yarris' case is just the latest example of why Pennsylvania should follow New Jersey's lead and give the death penalty a dose of sodium thiopental.

Beyond the fact that there is scant evidence that the death penalty acts as a deterrent, the overriding reason to eliminate capital punishment is that innocent people may be executed for crimes they didn't commit.

DNA testing has helped exonerate 210 people wrongly convicted of various crimes in 30 states. Texas has set free 15 inmates wrongly convicted in Dallas alone since 2001, including a man released this month who had spent 27 years in prison for a rape he didn't commit.

What's going on in cowboy country?

At first blush, it appears that Texas is locking up innocent folks left and right. But a closer look shows that an innocent man was freed because a Dallas crime lab preserved evidence going back three decades.

Conversely, there are countless people rotting in prisons across the country who are innocent but can't mount a credible claim because the evidence no longer exists.

DNA testing has been around only since 1988. The test helps in only a tiny fraction of crimes - mainly those involving rape - where DNA evidence exists.

Those wrongly convicted of a robbery or a shooting where there isn't DNA have a slim-to-none chance of overturning the verdict.

A review of scores of cases where a person was found to be wrongly convicted shows that the leading cause by far is eyewitness misidentification.

False confessions, government misconduct, lying snitches, and poor legal representation can all lead to a wrongful conviction.

All of those factors appear to have played a role in Yarris' case. Getting his verdict overturned was an uphill battle akin to winning the Powerball.

At one point, after contracting hepatitis C in prison and wanting to avoid dying from the painful disease, Yarris asked a judge to expedite his execution.

But after spending more than 8,000 days behind bars, Yarris narrowly escaped having the governor of Pennsylvania sign a death warrant for a crime it now appears he didn't commit.

That alone is enough to end the death penalty.