One of the staples of abolitionist argument is that the world has turned against the death penalty.
This is simply false. The Caucasian-dominated countries in Europe, plus Australia and Canada, have turned against it, that's true (although largely because of ruling class opinion as opposed to public opinion). There are some other abolitionist countries, mostly in Central and South America. But most of the world retains the death penalty.
This was brought home by this story of eight executions yesterday in Indonesia, the world's fourth largest country. All were for drug smuggling, none for murder.
The Indonesia story piqued my curiosity, so I took a look at the world's major countries, by population.
They are listed below. The world's two most populous countries by far are China and India, both of which have the death penalty. Of the ten most populous countries, all but Brazil and Russia have it (and I am counting Putin's Russia as among the abolitionist countries notwithstanding some reason to believe that it has a, shall we say, less formal death penalty).
1. China 1,355,692,576 2. India 1,236,344,631 3. United States 318,892,103 4. Indonesia 253,609,643 5. Brazil 202,656,788 6. Pakistan 196,174,380 7. Nigeria 177,155,754 8. Bangladesh 166,280,712 9. Russia 142,470,272 10. Japan 127,103,388

I wouldn't use China or Nigeria as examples for any policy, but to support your point the rest minus Russia I think are are somewhat democracies (not so sure about Pakistan) or better.
And I agree re Russia, if our Boston Marathon bomber had performed a similar deed back home for him, he'd most certainly be dead by now and probably in a very painful way.
I fully agree that China and Nigeria should not be used as examples for policy, and still less for how a judicial system should operate, as concerns the death penalty or anything else.
My own view is that Russia has a form of "capital punishment," which manifests itself as "accidents" or "disappearances." But still, abolitionists insist on counting it as among the countries that have put aside the death penalty.
If I were them, I would be more circumspect......but I'm not them.
I would add that Brazil has, for example, a (reported) murder rate which is about 4 or 5 times that of the U. S. Brazil is also where the first - or at least, the most famous - police death squads were alleged to exist, as a response to widespread and unanswered criminality in which gangs controlled & supplanted legitimate government in large parts of major cities. It has also been reported that the true murder rate in Brazil is widely underreported so as not to harm tourism and/or the 2016 Olympics.
In other words, Brazil is hardly the model for future abolition of CP.