The Supreme Court on Tuesday threw out the murder conviction of a Louisiana man because the jury that convicted him was given an impermissible definition of "beyond a reasonable doubt."

The justices unanimously ruled that Tommy Cage, currently an inmate on Louisiana's death row, is entitled to a new trial.In other action, the court:

- Set aside a ruling that let Louisiana officials give mind-altering drugs to a convicted mass murderer in the hope he could be made sane enough to execute.

The justices ordered a state court to restudy its ruling in the case of death row inmate Michael Owen Perry. The one-paragraph, unsigned opinion ordered reconsideration of the case in light of a Supreme Court opinion in February permitting prison officials to force inmates to take powerful anti-psychotic drugs without a judge's consent.

- Turned down the bid of an Ohio legislator, Robert E. Netzley, to avoid a libel lawsuit for using the term "Mafia" in opposing the re-election of James P. Celebrezze to the state's highest court.

The court, without comment, left intact a ruling that Netzley, a Republican member of the Ohio House of Representatives from Miami County, must defend himself against Celebrezze's lawsuit.

- Turned away an effort by Tom Perdue, onetime top aide to Georgia Gov. Joe Frank Harris, to kill a libel lawsuit against him by state Public Service Commission member J. Mac Barber.

The court, without comment, let stand a ruling that Barber's allegations that Perdue falsely accused him of bribery should go to a jury.

Cage had been convicted of fatally shooting Arthur Johnson while robbing him of a gold chain and medallion on a New Orleans street corner April 16, 1986. Cage had been sentenced to death for the crime.

Jurors who convicted Cage were told they had to conclude he was guilty beyond a reasonable doubt.

The judge said, "This doubt, however, must be a reasonable one . . . What is required is not an absolute or mathematical certainty, but a moral certainty."