The Supreme Court's July 24 decision that reduced the prison terms of a couple convicted of fatally abusing their daughter has highlighted the difficulty in balancing the need, on one hand, to have ordinary citizens' views reflected in criminal trials through their participation as lay judges and, on the other hand, to maintain consistency with judicial precedents.

The top court ruling may serve as a caution against the tendency of lay judge trials to impose more severe punishments on defendants found guilty. But too much emphasis on precedent can defeat the very purpose of the lay judge system introduced five years ago.

In rejecting the district and high court rulings on the couple charged with assault that resulted in the 2010 death of their 20-month-old daughter in Neyagawa, Osaka Prefecture, the top court sentenced the victim's father to 10 years in prison and gave an 8-year prison term to the mother.