The law of the United States is derived from the common law of England which was in force at the time of the Revolutionary War, but the supreme law of the land in the United States is the United States Constitution which forms the basis for federal laws under the federal constitution in the United States circumscribings the boundaries of the jurisdiction of federal law and the laws in the fifty U.S. states and territories.

Unlike the rest of the country, state law in Louisiana is based on the Napoleonic Code, inherited from its time as a French colony.

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