Last week, the people of Oklahoma tried to kill someone.

As you may have heard, they made quite a hash of it.

The execution of a Clayton Lockett by lethal injection turned into a horrific chain of errors. Prison personnel Tasered the inmate, struggled to find a vein, then botched the injection protocol. Things went so badly a prison official tried to call off the execution. Lockett died anyway.

A great noise is being made about this, as though one's judgment on capital punishment should hinge on whether it's done efficiently.

Here's another way to look at it. Oklahoma achieved its objective: ending Lockett's life. The rest is detail, beside the point morally.

If you oppose the death penalty on principle, the Oklahoma mess is a tricky talking point. To harp on it is to imply that the state-ordered killing would have been just swell if only they' hadn't botched the method.

I'm against executing prisoners, period. Even awful people such as Lockett. This view stems from my religious faith. But I understand that other people of good will can disagree, and that my religiously informed view is binding on no one else in this secular democracy. To persuade anyone, I need to make factual, logical arguments of a secular nature.

So here goes:

Killing people who are in custody is a strange way to teach that killing is wrong. No evidence exists that executions deter homicides. In fact, statistics show that murder rates run higher in death penalty states, often by a lot.

Most important, according to a study, 4.1 percentn of death -ow inmates over a three-decade period were wrongly convicted. Yes, some convictions got overturned due to flaws in trials, not proof of innocence. But dozens nearly died for crimes they didn't commit.

And, in the years before DNA evidence was available, we can pretty sure some innocents did die.

Would you go to a hospital if you knew its bumbling surgeons operated on the wrong organ 4 percent of the time? Or merge onto interstate where 4 percent of drivers get killed?

How can we possibly shrug at this kind of error rate in a matter of life or death, and call ourselves a just society?

We can't really. The only question is how many more people will we kill wrongfully in the name of justice before we figure that out?