独立战争后,美国建立了联邦制的资产阶级共和国。政治革命奠定的自由民主制度成为美国的宪政思想,而为大众传播活动提供政治法律上保障的便是自由主义的传播制度和媒介体制的确立。“自由主义理论和其他关于大众通讯工具在社会中的地位 After the War of Independence, the United States established a federal bourgeois republic. The democratic and democratic system laid down by the political revolution has become the constitutional thought of the United States. The provision of the political and legal guarantee for mass media activities is the establishment of a liberal system of communication and media. "Liberal theory and others about the status of mass communication tools in society