The Jim Crow law was upheld because basing on the passage, laws can change social prejudice. This means that if the laws express that one race is superior to the other, people will believe that and will take this idea to practice, by discriminating and marginalizing the inferior race. But if the law expresses that all races are equal and that they all have the same rigths, people will believe this and instead of braking the law, they will respect and there will be no more prejudice.