FOR DEFENSIBLE REASONS, Gov. Robb has decided not to pardon Roger Trenton Davis, whose 1974 sentence for possessing and selling nine ounces of marijuana was an outlandish 40 years in prison and a $200,000 fine. Instead, the governor has cut his sentences to 20 years. This could mean parole in two years, which, all factors considered, would be a reasonable ending to a bad chapter in Virginia justice.

It was a jury in Wytheville that set the 40-year sentence, at a time when drug users in southwestern Virginia were going to prison at a rapid rate. Then as now, however, there were insinuations that the sentence was related to the convicted man's situation as a black man married to a white woman in a mostly white, rural area. This is germaine simply because the power to fix sentences was in the hands of juries, not judges.

Under such a system, inconsistencies in sentences for the same crime -- even within the state -- were bound to occur. For that matter, two of this man's friends fared quite differently at the time. One, a murderer, was serving 15 years for various offenses when he escaped, killed a man, was recaptured and drew a 20-year sentence. Another completed a seven-year term for rape, was freed and within 21 days was back in jail charged with another rape. That time, he got 10 years.

In the case of Roger Davis, even the prosecutor termed the jury's sentence too severe. Then three federal courts struck it down as unconstitutional in light of a national average sentence of 3 1/2 years for similar crimes. But in January, a sharply divided U.S. Supreme Court upheld the initial sentence. Aside from an absence of precednt for holding a sentence unconstitutional solely because of its length, the Supreme Court cited its objection to federal interference with the state courts in this case.

So what's a governor to do now? He might consider the time already served by the convicted man as time enough. But how should he factor in another five-year term and parole on a drug count that preceded the 40-year sentence? Should a man who was on parole at the time he committed a new offense be set free by extraordinary executive action now?

Gov. Robb chose to reduce the terms to conform to current lower maximums. Leniency was not the issue, fairness was. The governor handled it correctly.