The debate started two weeks ago, on May 1, right after Lockett, a convicted murderer, was tortured to death by Oklahoma officials. Matt Lewis wrote a reasonable piece at The Week laying out "The conservative case for capital punishment." He wrote: "I believe in second chances. I believe in reform and rehabilitation. But I also believe in evil."

Balko responded to Lewis's piece with a case for "Why conservatives should oppose the death penalty," in which he argued that conservative skepticism of government authority and competence—like the inability to execute someone in a manner that isn't torture—should never be more intense than in the context of capital punishment, when life is on the line.

I am a fan of both Lewis and Balko and I found the exchange smart, even refreshing. Lewis is right that there could be a role for the justice system's ultimate punishment. And Balko is right to point out that capital punishment in America today is meted out arbitrarily, and capriciously, often after dubious trials and appellate procedures, bad lawyering, and poor judging.

Here is where Lott enters the story. Last week, at National Review, he wrote: "There is overwhelming evidence that the death penalty deters murder and saves lives. Combine that with the fact that errors, few to begin with, are becoming ever less common, and objections to the death penalty are basically eviscerated."

I recoiled, not just because I don't believe for a second that there is "overwhelming evidence that the death penalty deters murder and saves lives" but also because I have spent the past five years chronicling the many ways in which legal and factual errors, along with intentional misconduct on the part of public officials, pervade death-penalty regimes around the nation.

Balko must have had the same reaction, because he responded a few days later. His piece is vintage Balko, a blend of sense and sensibility, and at its core is this line: "It’s when Lott starts citing statistics that his piece begins to fall apart." Balko asserted that Lott applied a "facile" way of interpreting statistics about the racial component behind capital punishment and that Lott unjustifiably downplayed the significance of exonerations in capital cases.

That, in turn, must have made Lott recoil. On Tuesday, Lott responded to Balko's column, reiterating at the end of his piece an old argument he has made many times before: "Most peer-reviewed studies by economists, as I show in my book Freedomnomics, find that each execution saves roughly 15 to 18 potential murder victims."

Following this conversation day-to-day, with its array of statistics and facts and studies and evidence, made my head spin. The debate can be boiled down, I think, to two primary components: 1) the racial disparity in capital punishment, and 2) the deterrent effect of the death penalty relative to the error rate of executing innocent people.