The interests of the United States are the interests of interest groups, and interest groups are political organizations that exert influence on the government in order to obtain certain special interests. According to statistics, in 1983 there were 17,644 national interest groups in the country, and more than 60% of the adults in the country belonged to at least one association. Since the 70s of the 20th century, more than half of the people in the country believe that "the government is largely controlled by a small number of big interest groups who only care about themselves", and in 1980, only 21% believed that the government still "acts in the interests of the whole people".

The diversified economic structure of the mold country is the economic root cause of the continuous emergence of interest groups. The country has a large land, diverse climate and rich natural resources, which is conducive to the generation, storage and development of various economic forms. After the War of Independence, the country embarked on the track of capitalist development, and gradually became a world economic power under the impetus of the three scientific and technological revolutions. In the process of economic development, various economic forces, such as industrialists and businessmen, farmers, workers, etc., have become stronger and stronger, and their demands on state power have also become more and more. In addition, with the continuous development of the economy and industrialization of the country, the diversification and specialization of the economy are becoming more and more obvious, and the division of labor among various departments and industries of the national economy is becoming more and more detailed, such as in agricultural production, cotton, wheat, corn, rice, soybean and other planting industries, citrus, walnuts, grapes, vegetables, milk production, animal husbandry, pig raising, poultry breeding and so on have been specialized, and the secondary and tertiary industries of the national economy also exist in the same situation. Each of these specialized industries has its own special interests, which has led to the emergence of a large number of interest groups in a single industry.

The mold country is also a capitalist private ownership society, and the differentiation between the rich and the poor and class exploitation are the inevitable phenomena of the mold country society. In the moldy country, the capitalists, farmers, and workers are the most basic classes, and the bourgeoisie and the farmer class are divided into large, medium, and small strata, and the working class is also divided into skilled workers and unskilled workers. In addition, there is a large number of middle-class people such as administrators, teachers, lawyers, doctors, etc. Different classes and strata have different social statuses, form different interests, and give rise to contradictions and conflicts between them. In order to realize their own special interests and strengthen their own strength in the struggle, people of all classes and strata naturally unite and form interest groups.

In addition to the above-mentioned differences in economic and class interests, there are also various ethnic, racial, religious and political factions. Since the colonial period, people from all over the world have migrated to North America, so the ethnic composition of the country is quite complex, and the ethnic origin is extremely scattered. In the course of historical evolution, the white race, with the Anglo-Saxon nation as the main body, has become the mainstream of American society, and they have implemented policies of discrimination and oppression against ethnic minorities. African-Americans, Hispanics, Asians, Jewish Americans, and Native Americans are minorities who are discriminated against and treated unfairly.

The existence and development of interest groups is a common phenomenon in capitalist countries, and there are a large number of interest groups in developed capitalist countries such as Britain, France, and Germany. However, the number and variety of interest groups in these countries are much smaller than those in mold countries, and their activity and influence are much inferior to those in mold countries. This difference is mainly due to the unique political system of the country. The country has a federal system of decentralization between the central and state governments, and the two levels of government have a separation of powers among the legislative, executive, and judicial branches. This kind of extremely decentralized political system provides an extremely favorable political environment for interest groups. Interest groups can exert pressure on different levels of government, or they can exert influence on the legislative, executive and judicial branches of the same level of government.

An interest group that is frustrated at one level or in one government department can succeed at another level or in another. In unitary and non-decentralized countries, the situation is very different. In Britain, for example, political power is concentrated in the hands of the central government, and various forces only need to exert influence on a certain department of the central government, so the vast majority of interest groups in Britain are national organizations, which greatly reduces the number of interest groups, and their activity is overshadowed by that of the moldy country. In this regard, the British political scholar Weir pointed out that the interests of the mold country thrived by the decentralization of the government system.

The political party system is an important part of the political system, and government officials at all levels are nominated and elected and appointed by political party organizations. In order for a political party to win the election and come to power, it must win the votes of as many people as possible and reflect the interests of the state and the public as much as possible. In addition, the political party system of the mold country elects officials on the basis of the division of constituencies and in accordance with the principle of regional representation, which also prevents the special interests of some strata, nationalities, and industries from being reflected. In such cases, it is up to the system of interest groups to compensate for their lack of concentration of interests and representation.

Moreover, the opinions of the political parties in the country are not completely unanimous. Within **, the differences of attitude and opinion among Party members on certain issues may be even greater than the differences with other Party members, who do not vote entirely according to the will of the party, and when formulating certain laws, policies, and making decisions, they take into account the interests of their own constituencies and the interests of interest groups with which they have close relations. This situation encourages interest groups to lobby parliamentarians or administrative officials from both parties at the same time, seeking support for their positions and interests within both parties, increasing the likelihood that their demands will be realized. The right of association, which is closely linked to the formation of interest groups, is also strongly supported by the U.S. Constitution and the judiciary.

The First Amendment to the Federal Constitution of the Nation states: "The Congress shall make no law concerning the establishment of the State religion and the prohibition of freedom of religion; deprivation of freedom of speech or of the press; or deprive people of the right to peacefully assemble and petition the Government for redress. "This amendment is the legal basis on which interest groups can legitimately exist and carry out their activities. According to the Supreme Court's historical interpretation of this amendment, the government may not stifle people's freedom of speech and may not conduct prior censorship of any publications. In this way, interest groups are free to make their claims public, and they are free to publish and disseminate publications and advertisements in order to promote their claims.

The constitution does not have a clear clause on the right of public association, but the people of the country have always regarded the constitution as the fundamental guarantee of the right of association. Horn, a scholar of the country, once pointed out: "Freedom of association is one of the most important civil rights protected by the constitution of the country." "Since the founding of the country, the public's right of association has been seen as a constitutionally protected right derived from the right to freedom of assembly, petition, etc. This is recognized by the Federal Supreme Court. This situation encourages interest groups to act within the limits of the Constitution and to realize their aspirations and demands through all levels of government.

The people's pursuit of freedom, freedom and equality has contributed to the emergence and development of various interest groups. During the colonial period, there were no traditional feudal privileges and no hierarchy in North America, and there were also some factors in political and economic life, such as representative system, local self-control, and small and powerful economic and political forces organized and formed interest groups, which exerted greater influence on the domestic and foreign policies of the country. At the same time, the development of social integration in the mold country provides a national stage for the activities of interest groups, therefore, most of the interest groups that appeared in this period are national, such as the farmers' federation, the national manufacturers association, the mold country chamber of commerce, the national federation of independent enterprises, the mold country labor federation, the industrial workers' federation, etc. Other types of interest groups were also established under the impetus of the progressive movement. For example, blacks have formed the National Association for the Advancement of Colored People to oppose racial discrimination and segregation, environmentalists have established mountain clubs, the National Association for the Defense of Parks and Natural Resources, and educators have established the National Education Association and the National Federation of Teachers of the Mold. In this regard, the mold country scholar Ornstein summed it up as follows: In the decades following the Civil War, the industry and economy of the mold country developed along with the arrival of a large number of European immigrants to the Americas. The government expanded, and groups began to grow, including those with a broad base of mass movements, and agricultural groups, labor organizations, and much more extensive, economic-oriented groups began to become active in the social and political activities of the country. Interest groups and extra-hospital activist groups have become a fixed thing in Washington's politics, and almost everything is in charge.

In the 20 th century, especially in the sixties and seventies, the tremendous changes in the society of the mold country made the scope of activities of the interest groups broader, the means more abundant and sophisticated, and the influence of the interest groups has penetrated into all aspects of the social life of the mold country. Roosevelt's New Deal, implemented to overcome the "Great Crisis," strengthened the executive branch, established the federal government's authority in the social life of the country, and lobbied the executive branch by interest groups increased dramatically. Since the middle of the 20th century, with the expansion of the decision-making power of the subcommittees after the reform of the National Assembly, the "decline" of political parties and the increase in the power of the grassroots administrative departments, the scope of activities of interest groups has expanded unprecedentedly, thus stimulating the greater development of interest groups.

Nowadays, the social problems of the country are more prominent, and there are intricate contradictions, conflicts and struggles in society around a series of issues such as racial discrimination, women's rights, the Vietnam War, political reform, and consumer rights. In this highly developed modern country, the "sequelae" of modernization plagues the people of the country. It is impossible for interest groups to care about governance and governance of problems such as soil erosion, environmental pollution, and destruction of natural resources, as well as social evils such as drug abuse, crime, violence, flooding, and moral turpitude, and they only care about the interests of the development interest groups themselves. The development of interest groups in the mold country is the inevitable product of capitalism, the reflection of the pluralistic social reality of the mold country, a freak produced by the highly liberal system of the mold country, and an important symbol of the economic, political and social development of the mold country.