American officials deliberately replaced civil law with common law in Missouri

Evidence

From the very first, American officials aimed “to assimilate by insensible means, the habits and customs of the American and French inhabitants; by interweaving some of the regulations of the latter into our Laws, we procure a ready obedience, without violence or complaint.” As the American population increased, more direct action supplemented these gentle and “insensible means.” A statute of 1807, applicable to what became Missouri Territory, repealed the civil law on wills and inheritance and introduced American intestacy laws and laws about wills. American lawyers lobbied successfully for a law that made the common law of England the basis of law in Missouri Territory (1816). — Lawrence M. Friedman, A History of American Law, 927