How do you know if the law is unjust

The general thinking is that a law is unjust if it doesn't square with natural law. This is certainly the view that was put forth in Martin Luther King's Letter from Birmingham Jail.

So, a law that was passed that treated people differently wouldn't square with the natural law that all humans are equal. And thus, one would have the obligation to disobey that law.

Answer: The correct answer is : An unfair law is a code that does not agree with the moral law, the unfair law is a human law and also degrades the human personality, for example the statutes of segregation. An unfair law is not a law. If a law is unfair, a person has the right to disobey it and even the obligation not to comply with it.