The cyclical theory refers to a model used by historian Arthur Schlesinger to attempt to explicate the fluctuations in politics throughout American History. Liberalism and conservatism are rooted in the “national mood” that shows a continuing shift in national involvement between public purpose and private interest. Each of these cycles includes a phase of dominant public interest, a transition phase, and a phase of prevalent private interest.
The cycles 
Schlesinger defined these to be “self-generating and autonomous”. They begin in the mentality of the masses, rather than creations of influential individuals of a time period. Leaders or politicians are representations of the “mood”, chosen to express the voice of the majority. Shifts in the national mentality are initiated when discontent with present conditions over time drives Americans to pursue a new trend that promises to satisfy the interest of the masses. This discontent, described by Schlesinger as “inextinguishable”, drives the cycles of change in national politics.
Modernity is the psychology behind the disenchantment of the people with their surroundings. As society modernizes, or advances, the external conditions around each individual evolves, therefore stimulating changes in the individual’s attitude. Over a period of time, the attitude towards society and its goals will become negative, and whichever stage (public purpose/private interest), will cease to be ideal. Studies and surveys show that in the 20th century, this critical time period to develop discontent has decreased, implying that people are quickly dissatisfied with the ever-changing society.
Shifts are produced by changes in the mood of the majority. When more and more people shift from one end of the “balance” to the other, the balance itself begins to tilt to the other side. However, the change in mood must be reflected in a diversity of ethnic backgrounds and social classes to take effect. The cycle is not a permanent transition. Periods of stability in each stage of the cycle (public purpose/private interest), Schlesinger presents the concept the “accumulation of change”. He stated that when certain changes near the end of a phase take effect, they become permanent, and are unaffected by later “swings of the pendulum”. Therefore, the proper way to model the cycles of American History is by using a spiral, or single helix.
Public purpose and private interest do not correlate directly with liberal or conservative, or the ideals of specific political parties. These two systems of American values, albeit distinct, evolved from common ideals and fundamentals of American philosophy. They might be considered different paths to reach a common goal. For example, for the common purpose of attaining popular sovereignty, both systems can be used. In terms of Public Purpose, freedom may be expressed in welfare and protection of social rights, but not of other rights like gun rights or food choice rights in modern times. In terms of Private Interest, freedom may be defined in the practice of a laissez-faire economy, the protection of property, or even in aspects of Social Darwinism.
Some shared values of public purpose and private interest have been defined by theorists. They include anti-absolutism, limitations of government, popular sovereignty, and personal freedom.
Private interest 
This value systems stresses on a non-interventionist government, especially in its economy. Resulting from the 18th century fears of tyranny and a strong federal power, the free society is where an individual controls his own actions. The government’s only functions are to maintain order and structure. The values of Private Interest bear strong resemblance to Adam Smith’s theories of the laissez-faire economy (free market) and also the invisible hand. Smith proposed that the collective result of individuals with a variety of purposes is an economy that will profit the entire society.
Ideally in a Private Interest system, government must respect the “sanctity of private property”. This means that individuals have the freedom to pursue their own interests, but also bear the responsibility for success or failure. One of the possible disadvantages of such Social Darwinism is that the wealthy rise to the top, leaving the poor to fend for themselves, although some poor and middle class people become rich as well and some rich become poor. Another problem that may be present is political corruption. Overall, “survival of the fittest” may lead to “concentration of power”, “evangelicalism”, and “limited citizenship”. In connection to history, periods of Private Interest are often associated with times of economic prosperity.
Public purpose 
The values of Public Purpose assess the reality, often the consequences of a certain revolution. In times of complex social relations and economic and political confusion, the need for equality and opportunity arises. Due to certain, recurring causes in history such as division in wealth and social class distinctions, the majority begins to question the meaning of “liberalism”. Schlesinger explains that in “modern liberalism”, the government must intervene to ensure the protection of the common good. The concerns with “social responsibility” and “commonwealth” often involve the regulation and control of the government. Compared to the stages of Private Interest, times of Public Purpose are usually ephemeral “bursts of reform”. The idealistic goals of this period are only to ensure that government intervention is possible in times of need. The ideals of Public Purpose might include a redistribution of wealth and power and the protection of civil rights.
These periods occur as the masses change its “mood”. Results are often increased tension and division. From Public Purpose to Private Interest, the transition involves tensions, violence, and even war, due to the exhaustion from reformation. In the transition from Private Interest to Public Purpose, the people may suffer economic depression caused by divisions of wealth and power, leading to a renewed cause for social reform.
During the study of American history, no time period may be defined entirely as one stage or another of the Schlesinger cycle, nor can all the aspects of an era be generalized as to be proceeding in one direction. The cyclical theory is a tool to analyze political, social, and economic change with philosophy, identifying recurring trends and correlations. However, the cycle is not accurate in predicting the events of the future, because historians in the present do not have the benefit of hindsight and may lack crucial knowledge and understanding of certain trends.
Overall, the historian Schlesinger believed that the cycles may lead to the ideal society where certain emerging definitions of freedom may gain the support of greater and greater numbers of people, ultimately proceeding towards the form of freedom that is “inclusive of every American”.
See also 
- Sweeney, Nathan, An Introduction to Schlesinger's "Cyclical Theory" of U.S. History
- Brown, Jerald (June 1992), The Wave Theory Of American Social Movements
- Goertzel, Ted (2001-06-08), Generational Cycles in Mass Psychology