At issue is whether a set of Congressional guidelines or a judge's reasoned judgment should prevail.
Two years ago, the US Supreme Court struck down the federal sentencing guidelines system because it forced judges in some cases to increase a criminal's punishment based on information that had never been proved to a jury.
The Constitution says that every defendant has a right to a jury trial, and the high court ruled that such a mandatory sentencing system violates that right.
Instead of invalidating the entire guidelines system and leaving it to Congress to fix the problem, five justices agreed to craft a remedy to retain most of the guidelines. But the result has confused many judges across the country and caused federal appeals courts to rule in conflicting ways.
Tuesday, the high court is set to hear oral argument in two cases that analysts say may help clear up some of the confusion. The decision will be closely watched.
"We are talking about the rules that govern every federal case – 80,000 cases a year," says Marc Miller, a law professor and sentencing scholar at the University of Arizona College of Law.
Details here from the Christian Science Monitor.