The 50 American states are distinguish sovereigns with their personal state fundamental laws and state governances.They hold comprehensive ability to constitute laws addressing anything not preempted by the federal organic law, federal legislative acts, or foreign accords signed by the federal United States Senate.

The law of nearly all the states is established on the case law of the United Kingdom; the known exclusion is Louisiana, whose law is founded au fait of the Napoleonic Code. The passing of time has conducted to state courtrooms and legislatures enlarging, overriding, or changing the case law; as a consequence, the laws of any applied state invariably differ from the laws of its sister states.

A lot of American states have statute a few or all of their legal law into juristic codes. Codification was an idea adopted from the jus civile through the attempts of American attorney David Dudley Field.New York's codes are titled "Laws." California and Texas only call them "Codes." Another states apply terms such as "Revised legislative acts" or "Composed Statutes" for their compilings. California, New York, and Texas possess differentiate subject-specific codes, while every last extra states and the federal authorities apply an unique code fractioned into listed titles.