Dylann Roof appears at a court hearing in Charleston, S.C. (Randall Hill/Pool Photo via Associated Press)

A CHARLESTON, S.C., jury convicted racist murderer Dylann Roof of hate crimes last month, and now the only question is whether the state will put him to death. We oppose the death penalty even for the Dylann Roofs of the world. But if the jury disagrees with us, at least it would hand down the ultimate punishment in retribution for a truly unusual crime and without a shadow of doubt about Mr. Roof’s guilt. The same cannot be said for many other cases that resulted in death sentences over the past several decades, in which the punishment was meted out too often, without the restraint that even death-penalty advocates should favor.

That is why we were heartened to read through the Death Penalty Information Center’s year-end report, which came out Dec. 21. The group found that 30 new death sentences were handed down in 2016, a drop of 19 from 2015’s historic low. In fact, 2016’s total represents the lowest number in decades.

Twenty people nationwide were executed, which is the lowest number in 25 years, and only five states carried out executions, the lowest number in 33 years. As usual, a few states stood out. Texas and Georgia put the most people to death. But even in these states, attitudes may be changing: The death penalty was issued only four times last year in Texas, and no one was sentenced to death in Georgia. In fact, California led the pack in death sentences, with nine, four of which were issued in Los Angeles County alone. That’s right: L.A. County equaled the entire state of Texas in death sentences. Ohio tied with Texas for the second-most death sentences.

There are many possible reasons for the waning use of the death penalty. Over the past several years, anti-death-penalty advocates have attempted to sabotage the machinery of capital punishment, making it difficult for states to source the drugs they inject into the veins of the condemned. With crime rates still near historic lows, one would also expect fewer death sentences around the country.

But we hope the trend also reflects shifting attitudes. It has long been clear that the death penalty is extremely expensive for the government to administer, ineffective as a deterrent to crime and too often has resulted in innocent people being sentenced to die. The practice of killing human beings, even with all the due process in the world, is also in tension with the inherent dignity Americans should ascribe to human life. The sooner the United States gets to zero executions, the better.