WHEN LYNN KIVI slapped her 9-year-old son in a Georgia grocery store, she couldn't have dreamed that just one smack would land her in jail, put her on the network news and propel her into the center of a continuing national debate over how Americans discipline their children.

"Will police now get involved with parents punishing their children?" asked one angry letter to the editor in the Atlanta Constitution.

"Total madness," fumed another.

Kivi, of Woodstock, Ga., was in a Winn-Dixie grocery store in May when her son, who reportedly was picking on his sister, talked back. She slapped him. Fifteen minutes later, in the parking lot, a police officer summoned by a store employee arrested Kivi.

She was charged with cruelty to children, a felony that carries a jail sentence of one to 20 years. Her husband cashed in his 401K retirement account to pay the $22,050 bond. However, a prosecutor has dropped charges against her.

Kivi sobbed upon hearing the news from the Cherokee County District Attorney's office. "That big, dark cloud hanging over our house has moved down the street," she said in an story in the Atlanta Journal-Constitution.

To many, the arrest was an outrage. Why were the police involved in a private family matter? they asked. And what's wrong with spanking, anyway?

"Is America going to spoil the child and do away with the rod?" one reader wrote to the Atlanta Constitution.

But there are those in America who believe that doing away with the rod won't spoil anyone. In fact, they say, it would raise children's self-esteem and stop youngsters from growing up to believe violent behavior is acceptable.

"Violence starts with physical abuse at home," said Adrienne Ahlgren Haeuser, a professor at the University of Wisconsin at Milwaukee School of Social Welfare and a founder of End Physical Punishment of Children-USA.

Five countries - Sweden, Finland, Denmark, Norway and Austria - have already made it illegal for parents to spank their children. Germany, stereotyped as the most discipline-conscious of countries, appears ready to pass a similar law.

Why isn't the United States on the list? Supporters of spanking say it's because of this nation's deep respect for parents' rights.

"We have a constitution," said David Hodge, who has done research into parent and child issues for Carroll County, Md., delegates. "We have privacy interests and liberty interests."

But opponents of spanking say the answer lies deep within the American character.

"I think it's because - God help us all - we have gotten used to expressing our feelings in a violent way," said Elaine Fisher, executive director of Parents Anonymous of Maryland.

A new poll shows the country divided almost evenly on the practice.

A survey by the National Committee to Prevent Child Abuse found that 49 percent of Americans had spanked or hit their children in the last year. That was good news to the committee: It was the first time a majority of parents reported they hadn't used corporal punishment.

A USA Today poll in April found that 67 percent of those surveyed agreed that "a good, hard spanking" is sometimes necessary to discipline a child. But opponents of spanking could find reason to cheer that result as well: The number was down from 84 percent in 1986.

Twenty-six states have banned spanking in schools. And many child-care authorities such as Dr. Benjamin Spock and Dr. T. Berry Brazelton recommend that parents try other means of discipline before resorting to spanking.

"When you say spanking's acceptable," Fisher said, "you're including in that some parents who don't know when to stop. What starts off as a spanking can become something much more serious.

"We've grown to feel hitting a child doesn't hurt them, that it runs right off their back," she added. …