Before laws were written, there was no sure way of knowing what was permitted and what was forbidden. One judge might apply one set of rules to a case while another judge might apply completely different set of rules to a similar case. It all depended on the personal judgment of one person. Today we follow the custom of recording our laws. Rules passed by our lawmakers are printed and available for everyone to use. Unless laws are publicly available, we do not regard them as binding. Each of us is subject to many different sets of laws. Some laws say what is permitted, such as how fast you may drive. Other laws say what is required, such as paying a federal income tax. Still other laws say what is prohibited, such as smoking in elevators. In the United States, federal laws apply to everyone and state laws apply only to activities within each state.