There are many different beliefs and theories of what law is and who is subject to those laws. Each one is radically different, and causes dispute.
Some believe in Natural Law. This is the belief that there are laws that are imbedded in nature or inside our hearts, that tells us what is wrong and what is right. This, however, causes controversy, because everyone has their own feelings and morals. Right and wrong will vary from person to person. This type of thinking has a hard time holding up in court.
Some believe that each person or country can set down its own laws and do not have to submit to the law of others. This, too, causes controversy. It means that we should not have punished Nazi Germany for persecuting the Jews, or taking over other countries. According to German law it was perfectly legal. So we had no right. But because we have International law we were able to stop Germany and try to make so they could never do it again.
Some believe that God created the world, but then left it to run on its own. They believe he is impersonal and does not care what we do. Therefore we must make up our own laws based on our experience, feelings, and reason. And again controversy arises, for obvious reasons.
As Christians, we believe that God is creator of all things. He is a personal God and cares for us deeply. In the Bible he laid down laws of right and wrong for us to follow. With the Bible as our standard, there is no room for controversy. The important laws are in black and white. Do not kill, do not steal, ect. We do not have to make our own laws. We can simply follow Gods law and have perfect harmony.