The significance of this case, which was decided in 1982, was that it strengthened the due process protections for parents who are in danger of having their children removed from their care by the state.
Before this case, some states had laws in which they were allowed to take children away from parents if the court found that there was a "fair preponderance" of evidence to show that the parents' rights should be terminated. In Santosky, the Court made this requirement a bit more stringent. It held that the state had to have "clear and convincing" evidence that the children were being neglected by their parents. This meant that it would be harder for the state to remove children from their parents' care. Therefore, this case was a significant win for parents, bolstering their right to keep their children.