In 1984, the U.S. Sentencing Commission, an agency of the judicial branch, was set up to issue… In 1984, the U.S. Sentencing Commission, an agency of the judicial branch, was set up to issue binding guidelines for federal judges. The Supreme Court ruled Tuesday that federal judges have been improperly adding time to criminals’ sentences, in a decision that places doubt on longtime sentencing rules.

CBS News Legal Analyst Andrew Cohen said, “The court didn’t outright strike down the federal sentencing guidelines, but clearly those rules now are in jeopardy.”

The federal guidelines are intended to make sure sentences do not vary widely from courtroom to courtroom, but the 5-4 ruling said the guidelines violate the constitutional jury-trial right by forcing judges to increase the range of possible sentences based on factual findings.

For example, the guidelines direct judges to lengthen fraud sentences when an especially large amount of money is involved or the defendant is accused of playing a leadership role. But under the new ruling, former Enron Corp. Chairman Kenneth Lay or former Dynegy Executive Jaime Oils may have new bargaining power to try for shortened sentences.

The ruling also affects thousands of drug cases. Judges typically base federal drug sentences on the quantity and type of drugs involved.

The way the judicial system is set up, a jury considers innocence or guilt while judges make decisions about length of prison time. Facts may prove who committed a crime, but to ensure that the punishment fits the crime, a judge needs discretion to hand down sentences.

For example, a Wisconsin jury convicted Freddie J. Booker of possessing and distributing crack cocaine. The jury concluded that Booker had 92.5 grams of crack, an amount that requires the maximum prison term of 21 years and 10 months. But during sentencing, the trial judge found that Booker had distributed an additional 566 grams and had obstructed justice. There is no way the jury could have known this, but with the new information, the judge sentenced him to 30 years. That sentence was within a permissible range given the new amount and charge.

Justice can’t be served if a long-time drug trafficker and a one-time dealer receive the same punishment. It must be up to the judge to, well … judge, what sentence is suitable. That doesn’t mean a judge should have free reign over sentencing. Judges, like anyone else, must operate within the boundaries of the law. That is why these federal guidelines were constructed.

The Supreme Court justices stand by their decision that juries — not judges — should consider factors that can add years to defendants’ prison sentences. Yes, juries’ recommendations should be considered, but judges are the professional interpreters of the law.