According to Atticus, what did it take to make the grown men come to their senses?

“So it took an eight-year-old child to bring ‘em to their senses, didn’t it?” said Atticus. “That proves something—that a gang of wild animals can be stopped, simply because they’re still human. Hmp, maybe we need a police force of children... you children last night made Walter Cunningham stand in my shoes for a minute. That was enough.”