When Troy Davis was executed in Georgia Wednesday night, I immediately thought of Dennis Dechaine.

Dechaine is the Aroostook County native who was convicted in 1989 for the murder of Sarah Cherry in Bowdoinham. The victim, just 12 years old, was babysitting at the time, and Dechaine was quickly arrested by police. I was a young editor, and the case was a big local story – as it still would be today.

Almost from the time of his conviction, there have been doubts about whether Dechaine was guilty, and his supporters continue to press the case that he should get a new trial, 22 years after he was sentenced to life in prison without parole.

Dechaine is now 53, and no one knows if he will ever be able to show he’s innocent. But at least he still has the chance.

Troy Davis does not. Georgia is one of the states – 34 in all – that still have a death penalty, and it is also one that uses it relatively frequently.

The Davis case, which included an international campaign against his execution, leaves most of the world puzzled about American justice. Most of the eyewitnesses who identified Davis as the killer of an off-duty police officer recanted their testimony, and there was no physical evidence tying him to the shooting. If that isn’t reasonable doubt, what is?

The death penalty has long been a conundrum. The United States is the only major democracy still to impose it, and differences between states on the subject are large, and growing. The national debate will be sharpened by the Davis case, and by the prominence of Gov. Rick Perry in the Republican presidential field – Texas has conducted one-third of all executions since the Supreme Court restored the death penalty in 1976, after briefly putting it on hold.

Maine was the third state to abolish the death penalty, in 1887 – Michigan and Wisconsin did so earlier – and it came after a grisly spectacle where a condemned man slowly strangled before hundreds of spectators due to a poorly tied noose. There’s never been a serious effort to restore the death penalty here, despite the waxing and waning of public opinion.

A Washington Post writer asserted this week, citing a recent Gallup poll, that public support for the death penalty “has risen drastically over time,” but that is not what Gallup says. The polling firm has been asking since 1937 whether people support the death penalty for murderers, and the trends are suggestive.

For years, about 60 percent supported the death penalty, but as the civil rights movement gathered force in the 1950s, that began to change, as the crime of lynching and racially-biased justice came to the forefront. For one year – 1967 – more respondents opposed the death penalty than supported it.

Then came the 1970s, rising crimes rates and the “tough on crime” response. Approval for the death penalty rose sharply, reaching an all-time high of 80 percent in 1995. Since then, falling crime rates and DNA evidence showing many death-row prisoners were wrongly convicted have brought the numbers back down. When Gov. George Ryan, an Illinois Republican, suspended the death penalty there, no fewer than 13 prisoners sentenced to death were exonerated, leaving only 12 on death row.

At the peak, 37 states had death penalties, but since 2007 New Jersey, New Mexico, New York and Illinois have all joined Maine in abolishing it, and more than a dozen other states haven’t executed anyone in decades. There’s scant evidence having a death penalty deters murder. The Southern states that perform nearly all the executions also have the nation’s highest murder rates.

A national ban on capital punishment does not seem likely through the legislative process, however. The emotions about it tap into some of the darkest parts of the human psyche, and are hard to resist. In almost all nations where capital punishment has ended, it was through the courts, not the legislative process.

There’s something else: In most of these countries, a popular majority for the death penalty still existed. Yet in almost every case, with the alternative of life without parole, that support melted away, and capital punishment became what it has been in Maine – virtually unthinkable.

Despite its increasing right-wing bent, the present Supreme Court has erected new barriers to capital punishment – most importantly, forbidding the execution of those convicted as juveniles. Some day, even this court, prodded by more state legislatures, may declare capital punishment unconstitutional. And an eye for an eye will no longer be the law of the land.