Abstract: The United States is a large-scale economy and a federal country composed of 50 states with considerable autonomy. In its early days, interstate market segmentation was evident and local protectionism prevailed. However, the U.S. has now established a relatively complete unified national market, and its successful experience is worth studying and learning from. This article explores this history and finds that the principle of the United States in promoting the construction of a unified large market is: through continuous improvement of the rule of law, promote the federal government to unify economic policies and ensure the free flow of factors and goods. Among them, the rule of law ran through the history of the formation of a unified market in the United States and played the most critical role. The rule of law fundamentally limited local governments' discretion to implement local protectionism and provided a highly certain institutional environment for the free flow of factors.
First, the historical experience tells us that utilizing the rule of law to "overcome local protectionism and retain its incentive for economic development" is of significant importance in promoting the formation of a unified large market. Second, the U.S. government actively promoted the construction of transportation facilities nationwide, which effectively promoted regional economic development. At the same time, relevant legal construction eliminated obstacles such as local protectionism and monopolies, promoting the formation of a unified commodity market. Third, the United States continuously improved the legal construction to promote and encourage the free flow of labor, and established a nationally unified social security system, promoting the formation of a national labor market. Fourth, in promoting the marketization of land factor transactions, advancing the rule of law still played a core role. The government established the basic price of land, advanced the rule of law to achieve "same land, same price, same rights", and ensured the marketization of transactions.
