During a break in the Nixzmary Brown murder trial in Brooklyn last week, Jeffrey T. Schwartz, the lawyer for Nixzmary’s stepfather, described the predicament he said his client found himself in.

“You don’t know you’ve crossed the line until you get accused of crossing the line,” he said.

Whether Cesar Rodriguez, who is accused of beatings and abusive behavior that killed his 7-year-old stepdaughter, could not have known he had crossed a line is a matter for a jury to decide. He has admitted that he routinely beat Nixzmary with a belt, hit her with his hands using “all my force,” threw her on the floor. He has admitted duct-taping her emaciated 37-pound frame to a chair and binding her with bungee cords.

But at least in a broad legal sense, Mr. Schwartz has a point. The laws in New York State, as in the rest of the country, are vague on corporal punishment.

Parents in all 50 states are allowed to hit their children. In his opening argument, Mr. Schwartz reminded the jurors that most of them had said during jury selection that they had been hit as children and noted that parents have widely varying styles of discipline.