University of Utah law professor Paul Cassell rehearsed his arguments in moot court sessions as he prepared to make the case before the U.S. Supreme Court that enforcement of the court's 1966 Miranda ruling should be tempered.

"The basic argument is we shouldn't have this inflexible exclusionary rule that throws out voluntary statements just because there was some small mistake in the Miranda warning," Cassell said Monday.Last year, the 4th U.S. Circuit Court of Appeals sided with Cassell and ruled that statements made by Charles Thomas Dickerson, a suspect in a Virginia bank robbery, were admissible even though he had not been given the Miranda warning.

Cassell contends a 1968 law loosened the restrictions imposed by Miranda and allows voluntary confessions to crimes to be admitted as evidence, even if suspects aren't read their rights.

"This will make a relatively modest change in procedures (if the Supreme Court upholds the 4th Circuit)," Cassell said. "We are not asking the police to change Miranda warnings, we are asking the courts to re-evaluate their views and to stop tossing out confessions based on very minor omissions of Miranda."

Cassell, who is representing the conservative Washington Legal Foundation, raised the issue in a friend-of-the-court brief to the 4th Circuit.

On Wednesday, Cassell will get 30 minutes to present his case and answer questions from the Supreme Court.

Arguing against the 4th Circuit ruling will be the U.S. solicitor general and an attorney for Dickerson.

In a brief signed by Attorney General Janet Reno, government lawyers argued the 1968 congressional law cannot be enforced because the Miranda decision "is of constitutional dimension" and "cannot be superseded merely by legislation."

Cassell spent Monday polishing his arguments in moot court sessions in Washington organized by the Heritage Foundation. Students from Cassell's law class in Salt Lake City joined their professor in the moot court workouts.

"I've been working on this for eight years, so it's exciting to finally reach the Supreme Court," Cassell said.

"I've heard it's somewhat like taking a final exam -- you can study some but mostly you rely on your life experiences and your life work," he said.