Law is a system of rules that governs society and the people who work in it. It can deal with crimes, business agreements and social relationships.
Legal systems serve different purposes in a nation: to keep the peace, maintain the status quo, protect individual rights, promote social justice, and provide for orderly social change. Some legal systems do better than others at these tasks.
The most common definition of law is that it is a set of rules that a government makes, which citizens must follow or face punishment for breaking. Examples include laws that say you must not steal and those that say murder is against the law.
A criminal case is a trial where someone is accused of breaking the law and tried for it by a judge. The court might decide to have the person go to jail.
During the trial, the lawyers for the plaintiff and defendant will present evidence about what happened. They will also tell the jury what they think is right and wrong.
Lawyers will also use evidence that is not directly available from the witnesses to help them make their case. This may include circumstantial evidence such as eyewitness testimony and documents that the opponents have in their possession.
Law can be based on court decisions, as in common law systems, or on statutes adopted by the legislature and regulations issued by the executive branch. In common law systems, courts use the principle of stare decisis (Latin for “to stand by a decision”) to ensure that the same court’s decision is followed by lower courts and future cases.