 
 <prompt> Wetin be di legal doctrine wey dey make court to dey follow old cases wen dem dey make judgement on top similar case? Given di question wey dey up, write one context wey get di answer. E fit be 1 - 20 sentences. Context: <response>: Federal law dey start with di Constitution, wey give Congress power to make laws for certain limited purposes like regulating interstate commerce. Di United States Code na di official compilation and codification of di general and permanent federal laws. Many laws give executive branch agencies power to create regulations, wey dey published for di Federal Register and codified into di Code of Federal Regulations. Regulations generally also get di force of law under di Chevron doctrine. Many lawsuits dey based on di meaning of a federal law or regulation, and judicial interpretations of such meaning get legal force under di principle of stare decisis. 