Law and ethics may differ in what they allow or require a person to do. For example, some actions may be legal yet not ethical. A historical example is the legality of slavery in the United States until the Civil War. More recently, a nurse in Oregon might legally have assisted a patient to commit suicide, although the American Nurses Association declared that such assistance was unethical. Other actions may be ethical but not legal. A historical example would be the development of the Underground Railroad to assist slaves fleeing to Canada. This dichotomy can occur because legal rights are grounded in the law and ethical rights are grounded in ethical principles and values. The law establishes rules that define a person's rights, obligations, and the appropriate penalty for those who violate it. Moreover, the law describes how government will enforce the rules and penalties. There are many laws that affect the practice of nursing, and nurses must be able to differentiate between ethical claims that suggest how a nurse should act and legal requirements for the nurse to act in specific ways or potentially incur sanctions.