A man caught in Lawrence with 190 pounds of marijuana is among the first wave of defendants affected by a U.S. Supreme Court decision that revolutionized federal sentencing laws.

When Edgar Illescas appears for sentencing next month in U.S. District Court in Kansas City, the judge handling the case, John W. Lungstrum, will have more discretion than federal judges have had in decades.

The reason is that last month the Supreme Court told judges they’re no longer required to follow sentencing guidelines — a strict set of rules begun in the mid-1980s to ensure similar penalties for similar crimes. From now on, judges need only consult the guidelines.

The ruling in U.S. v. Booker has stirred debate about how appeals will be handled, how judges will respond to their newfound freedom and whether Congress will strip them of it.

One concern is that judges who disliked the guidelines will stop following them and give lesser penalties. Justice Antonin Scalia wrote that the guidelines have been “notoriously unpopular” with some judges.

Last week Lungstrum, a Lawrence resident and the chief judge for the state’s federal courts, gave one of the first indications of what Kansas judges would do.

“In short, although the sentencing guidelines are now advisory and not mandatory, the court believes they are entitled to great weight,” he wrote. “They are persuasive authority of the highest order.”

Eric Melgren, U.S. Attorney for the District of Kansas, credits the guidelines with helping bring crime rates down by requiring standard sentences for people he called “the baddest of the bad.”

He was encouraged by Lungstrum’s comments.

“We’ve started to get a feel of what our Kansas judges will do, and I’m pretty comfortable,” he said.

The guidelines are a grid that combines the person’s criminal-history score with the severity level of the crime.

The Supreme Court found the guidelines unconstitutional because at sentencing, judges had to find additional facts — often based on reports by probation officers — that hadn’t been proved to a jury or admitted in a plea.

For example, the judge might find that even though the defendant was convicted of dealing 5 pounds of marijuana, he dealt 10. In effect, people could be convicted of one crime and sentenced for a more severe crime.

The court’s fix was to let judges give any sentence within the statutory minimum and maximum, as long as they consult the grid first.

“I think it was extremely important to give sentencing discretion back to the judges,” said Terrence J. Campbell, a Lawrence attorney.

Illescas was arrested in August after picking up a load of marijuana disguised as a T-shirt shipment at a North Lawrence business. He recently entered a plea to possessing with intent to distribute more than 60 kilograms of marijuana and conspiracy to distribute more than 100 kilograms of marijuana. He’ll be sentenced March 28.

His attorney did not return a call seeking comment.