The New York Times' Adam Liptak reported Tuesday on a new, as-yet-unpublished study that seems to offer the most conclusive evidence yet that the administration of the death penalty in at least one part of the U.S. is biased by race.

Previous studies have shown repeatedly that the race of the victim had a significant correlation with prosecutorial decisions to seek the death penalty and jury decisions to impose it. This latest paper (available in PDF here) found that, in the one Texas county studied, the race of the accused was also a significant factor. (The paper's author, Scott Phillips, a professor of sociology and criminology at the University of Denver, doesn't claim deliberate discrimination -- he writes, "Because human motivations are unobservable, scientific methods cannot be used to determine whether disparities are intentional or unintentional, conscious or unconscious.")

According to Liptak, Phillips found that for every 100 white defendants and every 100 black defendants indicted for capital murder, 12 whites were sentenced to death, compared with 17 blacks. Liptak notes that the district attorney's office in question disputed Phillips' results and pointed out -- correctly -- that at the time the study was conducted, the D.A.'s office sought the death penalty in a manner essentially proportional by race. Phillips counters by saying that statistic is misleading, as the kinds of crimes whites were charged with differed from those blacks were charged with. Liptak reports, "Once the kinds of murders committed by black defendants were taken into consideration -- terrible, to be sure, but on average less heinous, less apt to involve vulnerable victims and brutality, and less often committed by an adult -- 'the bar appears to have been set lower for pursuing death against black defendants,' Professor Phillips concluded."

Liptak did turn to another academic who was skeptical of Phillips' work, Jon Sorensen, a professor of justice studies at Prairie View A&M University in Texas, who called the study "bizarre" and said, "It starts out with no evidence of racism. Then he controls for stuff."