There are several reasons we seem to be moving toward de facto abolition of the death penalty. A major one has been the growing number of inmates on death row who have been exonerated — 139 and counting since 1973 according to a list maintained by the Death Penalty Information Center. Even many people who support the capital punishment in theory balk when they are confronted with clear evidence that innocent people are being sentenced to death.
Another factor is costs. Money is tight these days, and more attention is being paid to just how expensive death penalty cases are. A 2008 study found that California was spending $137 million on capital cases — a sizeable outlay, particularly since it was not actually managing to put anyone to death.
Then there is the ick factor. In other eras, executions were public spectacles — and people turned out in droves. But we tend to be more squeamish these days. Ohio briefly suspended its death penalty in 2009 after a gruesome episode in which technicians spent two hours trying, without success, to find a vein to use to administer a lethal injection.