GOV. ROBB has another hot potato to handle.

Just two weeks ago, he was faced with the job of correcting an extraordinarily severe drug sentence, and he dealt with it well. In that case, Roger Davis had been sentenced to 40 years' imprisonment for selling nine ounces of marijuana. He had been on parole from another 15-year sentence when the crime occurred, and had been convicted of other drug offenses as well. Even considering this record, the sentence was excessive, and the governor rightly reduced it to 20 years, making Mr. Davis eligible for parole in about two years.

Over the weekend, another case came to light involving one David T. McBride. There are some similarities to the Davis case, but there is also a significant difference. David McBride had never been convicted of a crime before he was arrested in l970 and charged with selling some LSD to a childhood friend. He was convicted of that offense by a Bedford County, Va., jury and sentenced by that same jury to an astonishing 50-year prison term. The judge later reduced the term to 25 years. After serving 31/2 years of that sentence he escaped while on an unguarded furlough and fled to Sweden, where he has married, had a child, opened a business and apparently led an exemplary life. While changing planes at New York's Kennedy Airport last month, he was identified on a computer check, arrested and will be returned to Virginia today. He, like Roger Davis, has asked Gov. Robb for a pardon.

Many considerations will enter into the governor's decision. First, of course, is the excessive length of the sentence. One wonders, in fact, how many other inmates of Virginia's prisons are serving such out-of- line sentences as a result of old drug convictions, and whether it isn't time to review all these cases. Next, there is the possibility that the state's attorney in Southampton County--the location of the prison from which McBride escaped--will insist on prosecuting him for that escape and add yet another sentence to his record. In the long run, though, it would be best if both the governor and the state's attorney considered the purpose of imprisonment and decided that in this case that purpose has been fulfilled. David McBride has already served 31/2 years on a first offense. His ordeal should serve as an example to the community at large and should satisfy the community that justice has been done. Finally, David McBride appears to have been completely rehabilitated and no longer in need of whatever counseling, training and other adjustment may be provided by a correctional institution. Sending David McBride back to prison would be a waste of $60,000 a year in Virginia taxpayers' money.