Answer:
Simply put, written laws are required to keep the rules and punishments universally fair. Fairness is very important in society, mainly because people expect it from those who are supposed to be governing them. If people feel something is unfair, they can react rather violently, and it may even split up the society into factions.
By organizing support of like minded people and organizing a protest of some sort whether this be holding up signs outside of Congress, or boycotting a particular good.