Innocent until (sort of) proven guilty

Gov. Mitt Romney (R) announced recently that he wants to reinstate the death penalty in Massachusetts. He plans to create a panel of experts that will propose a method for ensuring that no innocent person gets executed. But Governor Romney's proposal - stunningly naive - betrays a profound misunderstanding of the rule of law in the United States.

Any death-penalty expert will tell the governor that it is impossible to be certain that innocent people will not be executed. Most death-penalty cases do not even involve DNA evidence; they involve confessions, eyewitness identifications, and testimony from codefendants or jailhouse snitches.

All of these types of evidence are notoriously unreliable, as demonstrated by cases that do involve DNA. Of the more than 120 DNA exonerations in the past decade, defendants - even though innocent - gave confessions in nearly a quarter of the cases; in nearly 70 percent, an eyewitness identified the defendant as the wrongdoer. Had DNA not subsequently exonerated these men, we would have assumed, on the basis of a coerced confession or an erroneous eyewitness identification, that we had the right person. We would have been wrong.

But even if Massachusetts were to take the radical step of providing that the death penalty could be meted out to only those defendants whose guilt was established by DNA, human error could still intervene. In Harris County, Texas, for example, examination of DNA cases has revealed testing errors in scores of cases and misleading scientific testimony in hundreds. DNA is a powerful forensic tool, but it is still a tool that relies on human beings to perform testing and to testify to the significance of the results.

In short, an infallible death-penalty system is as impossible to attain as risk-free space travel or perfect mail delivery. And creating a panel to solve the "innocence" problem will not solve all of the problems with the death-penalty system.

Appointing a panel of experts does indicate that Romney, like the American public generally, appears to have been chastened by the fact that innocent people end up on death row. But why do people care about accidentally killing innocents on death row? We build interstate highways, for example, despite knowing that many hundred innocent men and women will be involved in fatal vehicle collisions as a result.

Someone who supports the construction of interstate highways does so in the belief that highways benefit society. Someone who supports the death penalty does so for similar reasons: Capital punishment improves society by creating a deterrent to or retribution for crime. The fact that innocent highway workers perish while building highways does not cause supporters of interstate highways to change their minds. So why does someone who originally supported the death penalty change his or her mind when confronted with the obvious fact that innocent people get executed?

The answer is that in the realm of criminal-justice issues, the concept of justice is relevant. It is tragic that innocent highway workers die, but it is not unjust - it does not violate a legal principle. One key principle in criminal justice is that of just desert: People should pay for the wrong they do, and not otherwise.

Executing innocent people violates this principle.

But there are other equally important principles that, taken together, form the fabric of the criminal justice system. Take, for example, the idea of equal protection. People should not be more likely to get sentenced to death just because they are black or poor, or because their victims were white. We know that in every jurisdiction that has the death penalty, people who murder white victims are four times as likely to be sentenced to death as people who kill blacks. We know that defendants with financial resources do not get sentenced to death, and often do not even get convicted.

A system that executes somebody on the basis not soley of the crime committed, but of factors of race or economic status, is simply wrong.

By focusing on one and only one principle Governor Romney ignores otherprinciples equally as important. We should obviously stop putting innocent people to death. But the death penalty is unjust - not simply because innocent people will die, but because many values are routinely abridged in order to keep capital punishment alive. Proving innocence matters, but it is not all that matters.

• David R. Dow is the Distinguished University Professor at the University of Houston Law Center, where he teaches constitutional law and death penalty law. He is coeditor of 'Machinery of Death: The Reality of America's Death Penalty Regime' (2002).