Law is a system of rules enforced by the government to regulate behavior. It is a fundamental aspect of modern society that requires the peaceful coexistence of billions of people. United States law functions at a federal and state level guided by common law and civil statutes.
Common law, also known as case law, is unwritten law based on legal precedent rather than legislation. A legal precedent is an earlier decision made by judicial authorities. According to the principle stare decisis, judges are bound to follow precedent to ensure consistency in the justice system. For example, a decision made by the United States Supreme Court binds all lower courts in the country to follow. In 2015, in Obergefell v. Hodges, the Supreme Court ruled that same-sex couples have the right to marry. Now all fifty states are required to perform and recognize same-sex marriage.
English Common Law had a significant impact on modern jurisprudence in the United States. Common law evolved in 11th-century England and predated the establishment of legislation. When Parliament acquired legislative powers, they were forbidden to change or limit common law (Castellano, 2009). Common law became a check on the power of the Parliament. This was dissimilar to all other European countries, which sought to limit judicial power and instituted a civil law system. As the British Empire imported its legal system to its colonies, the same relationship developed in the United States (Castellano, 2009). Now, common law balances judicial and legislative branches since it gives judicial authorities the power to make law by determining the interpretation of legislation.
Penal law, also known as criminal law, is a system of laws defining criminal offenses, regulating the procedure for apprehending and trying suspects, and fixing a punishment for convicted persons. Criminal law in the United States is beyond the authority of common law (Castellano, 2009). An example of criminal law is drunk driving and unintentionally killing a pedestrian. According to New York state law, this is defined as criminally negligent homicide punishable by up to five years in prison (Law Offices of Stephen Bilkis & Associates, n.d.).
In total, common law is a system of law based on legal precedent that originated in the common law courts of medieval England. However, criminal law is not subject to common law and depends on legislation. The existence of common and codified law ensures the balance of the judicial and legislative branches of government.
Castellano, D. J. (2009). Common law and civil jurisprudence. Arcane Knowledge.
Law Offices of Stephen Bilkis & Associates. (n.d.). NY Penal Law § 125.10: Criminally negligent homicide.