Seoul (CNN) The South Korean Supreme Court ruled in favor of conscientious objectors Thursday, ending the country's decades-long position as the world's leading jailer of those who refuse to join the armed forces.

"Refusing to enter the military due to a religious faith which forbids bearing arms is considered a justified reason to refuse duty," the court said in its ruling. "Therefore it cannot be criminally punished."

In overturning a ruling by a lower court to sentence a conscientious objector to 18 months in prison, it said jailing him "excessively limited his freedom of conscience" and threatened the essential protections of the country's constitution. The case has now been returned to the Changwon District Court.

In a dissenting opinion, a minority of judges said the ruling interfered with an issue of national policy "which should be solved via adoption of alternative service law" decided by the legislature.

The Supreme Court's ruling comes on the back of a decades-long fight by conscientious objectors, many of them Jehova's Witnesses, to push back against the country's stringent military service law, under which all men between the ages of 18 and 35 are required to perform at least 21 months of military service.

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