Few people in or out of the government realized that it is perfectly legal to pay witness fees to prisoners who testify in federal court.

When Chief Justice William Rhenquist, speaking for the Supreme Court, recently ruled that nothing in U.S. law bars such payments, it shocked several lawmakers as well as the Justice Department.The Supreme Court ruling overturned a long-standing and sensible federal policy against such payments.

The decision came as the result of a lawsuit filed by a Colorado inmate convicted of murder who appeared as a witness at a criminal trial. The inmate said the federal law requiring a witness fee did not prohibit payment to prisoners. Given the fact that the law does not mention any exception for prisoners, the high court was forced to agree.

It is estimated that the cost to the federal government of witness payments to prisoners would run between $8 million and $11 million a year for approximately 7,000 inmates.

For many in Congress this figure, as well as the idea of rewarding convicted criminals for their appearances in court, seems outrageous. Under federal law, witness fees were meant only to compensate law-abiding citizens for time lost from jobs and other for expenses, such as travel, as a result of being subpoenaed for court appearances.

Besides that, such payments to prisoners cast doubt on the validity of any testimony that is given in return for remuneration. Paying inmates to testify would look too much like having "hired" witnesses.

Fortunately, both the Justice Department and the House Judiciary Committee have expressed determination to push for a permanent ban of such payments. Congress should express itself loudly and clearly on this important constitutional issue - and the sooner the better.