Hawai'i's appellate courts have revisited the thorny question of when parental discipline becomes child abuse, this time overturning the criminal conviction of a stepfather who used a belt to spank his child.

The defendant, Marine Corps Staff Sgt. Jerry Robertson, was convicted of abuse of a household member in 2007.

The boy, 8 years old at the time, was bruised by the punishment but otherwise uninjured.

Family Court Judge Patrick Border sentenced Robertson to 10 days in jail and two years of probation, but delayed imposition of the sentence while the case was appealed.

This week, the state Intermediate Court of Appeals reversed the conviction in an 11-page decision written by Chief Judge Craig Nakamura.

According to case files, Robertson and his wife, also a staff sergeant in the Marine Corps, has previously used noncorporal punishment for misbehavior by the boy.

The spanking took place after the boy came home from school and lied to Robertson about his behavior at school.

"He lied to parents by saying he had 'a good day,' and he did not tell them about the negative note (from his teacher) in his notebook," the court decision said.

"Robertson soon discovered the negative note as well as an accumulation of other recent negative notes in the notebook of which Robertson had not previously been aware," the ruling said.

Because noncorporal punishment — such as taking away such privileges as television, toys, his allowance and sports — had not worked, Robertson told the boy to go to another room to be spanked.

After telling the boy to drop his shorts, Robertson explained to the child the reason for the punishment and gave him a chance to respond.

"Robertson then proceeded to spank child with a belt, for a period between one and two minutes," the ruling said.

Because the boy was "jumping around," only about eight of the attempted spanks actually made contact, according to Robertson.

Robertson said he had been disciplined the same way when he was child.

"Robertson intermittently stopped the spanking and talked to child, explaining to child why child was beng punished," the court ruling said.

Robertson was 6-feet-4 and 230 pounds. The boy was 4 feet tall and weighed about 50 pounds.

Robertson later told police that he used "about a quarter of strength" when striking the child.

The boy's mother said she did not believe the discipline was excessive and would have intervened if she thought otherwise.

The boy did not complain of pain that night or the next day, when he went back to school and once again misbehaved.

"Child told his teacher he did not want another note because he did not want to be punished," the decision said.

The teacher called police after the boy said "he had a received a whooping and showed her his buttocks and hip area."

A police officer observed "slight bruising" but the boy said he was not in pain and was not hesitant to go home. The office also interviewed Robertson and determined there was "no immediate danger of abuse or harm."

Two days later, the state office of Child Protective Services took the boy for a medical examination and a doctor found some 15 bruises but no open wounds on him.

The doctor did not know that the boy had been to flag football practice a day earlier.

In overturning Robertson's conviction, the appellate court cited a 2007 Hawai'i Supreme Court decision which said "parents have a privilege to subject children to reasonable corporal punishment."

The decision this week said Robertson's actions fell within the "parental discipline defense (which) is intended to recognize a parent's privilege to use force in disciplining his or her child as long as the force used is limited to that which is reasonable or moderate."

The ruling cited a New Mexico court decision which said, "An angry moment driving moderate or reasonable discipline is often part and parcel of the real world of parenting with which prosecutors and courts should not interfere.

"What parent among us can say he or she has not been angered to some degree from a child's defiant, impudent or insolent conduct, sufficient to call for spontaneous, stern and meaningful discipline?" the citation continued.

State Public Defender Jack Tonaki, whose office represented Robertson, said this week's ruling is consistent with previous decisions holding that "the state should not be delving into the area of parental discipline when it is applied within reason."

Deputy Public Defender Ronette Kawakami said she reached Robertson yesterday to notify him that his case was dismissed. She said Robertson would have no comment on the matter.