Handing the colony of Louisiana back and forth between their empires, the French and Spanish left a legacy that lives in such forms as the architecture of the Vieux Carre and a civil law deriving from the Napoleonic Code. Acadian refugees, German farmers, black slaves and free blacks, along with Italians, Irish, and the Kaintucks who helped Andrew Jackson win the Battle of New Orleans added to the state's distinctiveness. Made rich by sugar cane,...