Why do people agree to live by rules? One old answer comes from Hobbes. In 1651 Hobbes wrote that without government there would be no enforceable right and wrong, and life would be "solitary, poor, nasty, brutish and short." So, he said, people agree to give up some liberty to a sovereign. Social contract thinkers include Hobbes, Locke, Kant and Rousseau. Their idea is that the rules we live under can be explained as an agreement among people. Social contract theories were most popular in the 17th and 18th centuries, and they tried to justify government by comparing its advantages with life without it.

Hammurabi was a king of Babylon who ruled from 1792 to 1750 BCE, and his laws were written down. His code has 282 case laws. They cover prices and trade, marriage and divorce, theft and assault, and debt. His legal decisions were collected and carved into a stone pillar, so people could see them. The pillar was found at Susa in 1901 and is now in the Louvre in Paris. You may have heard that his code was the first written set of laws. In fact, Hammurabi's laws were built on Sumerian law that communities had lived under for many centuries, and the Sumerians had the earliest known law codes.

Law is the set of customs, practices and rules of conduct of a community that the community recognizes as binding, and it is enforced by a controlling authority. "A rule of law" is one particular legal rule, such as the rule that we must file our taxes by a certain date. "The rule of law" is a different idea: no one, even the most highly placed official, is above the law, and government is bound by existing laws as much as its citizens are.

King John of England granted Magna Carta, a charter of liberties, to his barons in 1215. It was reissued with changes in 1216, 1217 and 1225. You may have heard that it gave every person rights in 1215. In fact, when it was written, Magna Carta secured only the rights of a privileged class of the king's subjects. Over centuries it became an enduring symbol of liberty and the rule of law.

The United States Constitution begins with the words "We the People of the United States." It united its citizens as members of a whole and placed the power of the union in the people. The Constitution gives the power to make federal laws to Congress. A bill has to pass both the House of Representatives and the Senate before it can become a law, and bills for raising revenue must start in the House.

Traffic signs follow standards so drivers can recognize them fast. For example, stop signs always have a red background and are eight-sided. A traffic signal is a device used to control traffic, and signals mainly sit at city intersections, where they give each stream of traffic its turn to go. The National Highway Traffic Safety Administration says that keeping walkers safe is a shared job for pedestrians, drivers and everyone who uses the road.

NHTSA estimates seat belts saved 14,955 lives in 2017, and could have saved 2,549 more if those people had worn them. Seat belt laws raise belt use, especially when enforcement is publicized. The national seat belt use rate in the United States was 91.3 percent in 2025. In a crash, an unbelted person keeps moving at the same travel speed until crashing into what is in front of them.

The American Academy of Pediatrics suggests that families talk about their expectations and about reasonable consequences for not following family rules. The CDC suggests that when a child is told "no," the grown-up follows up with what the child should do instead. Health groups also say rules work best when they are clear and stay the same, and that a rule should be explained in words a child can understand.

In 1891 a teacher named James Naismith invented basketball and wrote its first rules. The first games used half-bushel peach baskets as targets, so a stepladder was needed to get the ball out. Naismith's original rules banned walking or running with the ball and limited physical contact, and they are still the basis of basketball. His first class had 18 players, so the first games had 9 on each side. Basketball became an Olympic sport at the 1936 Games in Berlin, and Naismith was there to see it.

Under the rule of law, laws should be open, clear and knowable to all. People must be able to consult them before acting, and a person should not be punished under a law made after the act. Ideas about the rule of law go back at least to the 4th century BCE, when Aristotle set the rule of law apart from rule by any one person. A good rule is clear and open, so everybody can know what it is. A fair law is for everyone the same, and equality before the law means no one gets special privileges.

Words to know

• liberty: freedom
• binding: must be followed
• reissued: issued again
• privileged: favored class