Due process is the right of all citizens to be treated fairly in any case where the may lose their life, liberty , or property. The reason why due process is important is because it can help save one's lift in a court case that was judged wrongly against them. And can help them in the long run to stay alive and find a way to get back stolen or misplaced property, and keep your freedoms.
Due process are certain rules and guidelines that must be followed when a person has a situation that involves any person that is employed as a government law enforcer. Due process makes it so that a police officer can't just rummage through your house or car without a warrant. As well as having them killing you because they feel like it. All of these ways that people that are supposed to help you, makes sure you have protection from these by due process.
If you are taken into court without being read your rights, and you have not been treated under due process. You have been violated. Due process is one of the best ways for the U.S. to keep it's country in decent shape as far as law enforcing goes. So that no one will be cheated or discriminated upon.