Utah's first legal challenge to new federal sentencing guidelines was filed Wednesday on behalf of John Timothy Singer, who was convicted on four felony counts in the Singer-Swapp trial.

Sentencing for Singer and the three other defendants is set for July 1. He was convicted of attempted second-degree murder of federal officers in the Jan. 28 shootout, using a firearm in the shootout, forcibly resisting arrest during the siege, and using a firearm in the resistance.The two firearms charges carry mandatory terms of five years in prison apiece, to be served consecutively. In the past, judges have had a certain amount of flexibility on the other counts.

However, under new sentencing guidelines that went into effect last November, U.S. District Court Chief Judge Bruce S. Jenkins will have little leeway in determining Singer's term even in those counts.

Utah U.S. Attorney Brent D. Ward estimated Thursday that Singer could be sentenced to something between one and three more years for those other counts, under the guidelines. But he said the terms haven't been calculated exactly.

The guidelines are being challenged around the country. In about half of the federal districts where the guidelines were attacked, judges have ruled them unconstitutional; in the others, they are ruled acceptable.

So far, no appeals court has ruled on the guidelines. The U.S. Supreme Court is expected to rule on the matter later this year.

G. Fred Metos, Singer's lawyer, filed his challenge Wednesday in the form of a motion in the criminal case.

"The courts that have been holding it unconstitutional have primarily gone off on the issue of separation of powers," he said. Under the Constitution, the judiciary is supposed to be separate from the executive branch, which enforces the laws.

However, new law requires that three federal judges sit on the sentencing commission that sets guidelines. This may amount to an improper performance of an executive-type duty, Metos said.

The commission continues to sit, "constantly updating" the guidelines. Members hear challenges to the guidelines and monitor all sentences imposed under the rules.

"There's a due-process violation in the way the guidelines are structured, because the guidelines don't allow judges to consider all of the relevant facts in imposing sentence," Metos said.

The system works like this: points are set for such things as the nature of the offense, the type (or lack) of prior record and the severity of the offense.

Using this, "they come up with a sentence," Metos said. The judge only has a slight leeway - perhaps six months of the term.

The defense lawyer said vital factors that should influence sentencing in this case can't be brought up under the guidelines - Singer's age, physical condition and education. "I think they're critical in his case."

Singer is a young, wheelchair-bound man who's had little formal schooling.

A federal district court in Colorado has already ruled against the guidelines. "We're also claiming that the guidelines themselves fail to meet the statutory effect sought by Congress," Metos said.

"We would defend (against) the challenge," Ward said. "I think that we probably would draw upon stock briefs that have already been worked up by the Department of Justice.

"These challenges are becoming fairly common around the country now."

Using the guidelines, it's possible that defense lawyers, prosecutors and federal probation officers will come up with different scores for the Singer-Swapp defendants. So a separate hearing will probably be necessary to clarify the situation.