WASHINGTON — In 2009, an Alabama jury convicted Christie Scott of murdering her 6-year-old son by setting a fire in her home. It then voted to spare her life.

Judge Terry L. Dempsey of the Circuit Court in Russellville rejected that verdict and sentenced Ms. Scott to death. “This jury was probably emotionally and mentally worn out,” he said, adding that jurors might have been swayed by testimony from the victim’s family seeking leniency.

A year later, on the other side of the state, a jury unanimously recommended that Courtney Lockhart, a veteran of the Iraq war, be spared the death penalty for murdering Lauren Burk, a college student.

Judge Jacob A. Walker III of the Circuit Court in Opelika overrode the jury’s verdict and sentenced Mr. Lockhart to death — but for the opposite reason. Judge Walker said Ms. Burk’s family had asked for the death penalty, which “weighs in favor of judicial override.”