UNLESS THE U.S. Supreme Court or Gov. Mark Warner intervenes, Virginia will put to death tomorrow night a man named Robin Lovitt for a murder at a pool hall in Arlington seven years ago. The evidence that Mr. Lovitt stabbed Clayton Dicks to death in a late-night robbery is strong enough to support his conviction. But it isn't overwhelming, and it should not be strong enough to support his execution -- particularly because the state has destroyed all of the physical evidence that might be ripe now for post-conviction DNA testing. This fact has not moved the courts so far. But Mr. Warner ought not permit execution of a man who has steadfastly maintained his innocence when the state itself has unlawfully made the final assessment of that claim impossible.

Virginia law obligates it to preserve physical evidence. This case is a good illustration of why. DNA testing at the time of Mr. Lovitt's trial was inconclusive; testing now might be more informative. Yet an Arlington court clerk -- over the objections of two subordinates -- arranged for the destruction of nearly all of the exhibits in Mr. Lovitt's trial. This was not, the courts have ruled, an effort to sabotage his case, just a good-faith administrative foul-up.

This distinction is potentially pivotal in federal court review of Mr. Lovitt's conviction and death sentence. It shouldn't be, however, for a governor considering commuting his sentence to life in prison without parole. Exactly why Mr. Lovitt has been blocked from precisely the sort of retroactive testing Virginia law seeks to ensure doesn't really matter, after all.

Even were the state's evidence ironclad, this isn't the sort of case that typically produces a death sentence. Under the state's own theory of the case, Mr. Lovitt killed Mr. Dicks -- a friend and former co-worker -- after being surprised while trying to steal the pool hall's cash box. It is a horrible crime, to be sure, but Mr. Lovitt is not the kind of worst-of-the-worst for whom the death penalty is normally reserved.

An execution in Mr. Lovitt's case would be unusually harsh for a crime of this type. It involves a risk, however small, of a grave injustice where the state itself has frustrated the legal means of averting that injustice. Mr. Warner should not let the commonwealth take that risk.