Nation: A Jury Sets Dr. X Free

For four months, the man mostly in the shadows at the Dr. X murder trial in Hackensack, N.J., has been the 51-year-old defendant himself, Mario Jascalevich. The Argentine-born physician was accused of killing five hospital patients in 1965 and 1966 by injecting them with lethal doses of curare, a muscle relaxant. His motive, the prosecution speculated, was to discredit other doctors who were challenging his authority as the hospital's chief surgeon.

But during the last half of the trial, far more attention was given to the constitutional confrontation that arose when the defense...