Repeal of the death penalty in New Hampshire is headed to the desk of Gov. Chris Sununu. He’s repeatedly vowed to veto the measure, but he ought to rethink that stance.

To begin with, it’s simply wrong for the state to be in the business of killing people. As a punishment, even for the most heinous of crimes, it’s uncivilized, overly costly and — importantly — irrevocable; it cannot be undone, even in cases where mistakes or injustices have been done. Further, one can reasonably make the case that a lifetime in prison is a harsher penalty than a relatively quick ending.

Moreover, it’s a political battle those with his view are likely going to lose. We say that not only because both the House and Senate backed House Bill 455 by wide enough margins to override a veto — though there is no guarantee the governor can’t sway enough lawmakers to his side to ultimately sustain such a move — but also because capital punishment is falling out of favor.

Nationally, a growing number of conservative lawmakers, traditionally the core of death penalty backers, are moving away from that stance. Efforts this year in Wyoming, Kentucky, Montana and Virginia to repeal or diminish capital punishment statutes have widespread Republican backing.

And in New Hampshire, support for repeal efforts has been growing among GOP lawmakers. In 2014, 56 Republican House members backed a repeal bill. Last year, 71 did. And HB 455 passed the House this term with 72 GOP votes, even as that party lost many seats in last November’s election.

Among the groups calling for repeal is Conservatives Concerned About the Death Penalty, which argued before the Senate Judiciary Committee last month that “the death penalty does not comport with conservative principles such as limited government, fiscal responsibility, and a commitment to life.”

New Hampshire has not executed anyone for a capital crime in 80 years. One man stands convicted of a capital murder and sentenced to die — Michael Addison, who shot and killed Manchester police Officer Michael Briggs during a robbery in 2006. Although the repeal bill ostensibly affects only future cases, former state attorney general Kelly Ayotte told the Judiciary Committee that she believes Addison’s death sentence would likely be commuted if it passes.

Addison’s future has been a central point in death penalty debates in recent years. Several gubernatorial candidates have said while they supported repeal, it would only be if it didn’t apply to him. Briggs’ widow testified before the Judiciary panel last month that her husband was a death penalty supporter, and she urged the senators to kill the repeal measure.

Such appeals are based on emotion, as is the death penalty statute itself. The idea of “an eye for an eye, a life for a life” may feel just, but it is born of rage, not logic.

As for the notion that putting a murderer to death will serve as a warning and deter others from similar crimes, that is, as Cheshire County jail Superintendent Richard Van Wickler testified, a fallacy that’s been debunked by many studies. “There’s no deterrent effect, specifically or generally. ... It doesn’t exist.”

Sununu looks to be ready to veto quite a number of bills this session. Many of them have been passed along partisan lines and there remain enough Republicans in both chambers to support his vetoes.

House Bill 455 is not in that category. If he cannot flip a handful of Senate votes or a larger number of representatives, Sununu stands to see a veto of this measure overridden. He ought to accept that it has bipartisan support and sign it, or if unwilling to do so, allow it to become law without his signature.