Gov. Haley Barbour of Mississippi has to decide whether to show mercy to two sisters, Jamie and Gladys Scott, who are each serving double consecutive life sentences in state prison for a robbery in which no one was injured and only $11 was taken.

This should be an easy call for a law-and-order governor who has, nevertheless, displayed a willingness to set free individuals convicted of far more serious crimes. Mr. Barbour has already pardoned four killers and suspended the life sentence of a fifth.

The Scott sisters have been in prison for 16 years. Jamie, now 38, is seriously ill. Both of her kidneys have failed. Keeping the two of them locked up any longer is unconscionable, grotesquely inhumane.

The sisters were accused of luring two men to a spot outside the rural town of Forest, Miss., in 1993, where the men were robbed by three teenagers, one of whom had a shotgun. The Scott sisters knew the teens. The evidence of the sisters’ involvement has always been ambiguous, at best. The teenagers pleaded guilty to the crime, served two years in prison and were released. All were obliged by the authorities, as part of their plea deals, to implicate the sisters.