The study investigated the relationship between leadership transitions and the political and economic social context. We concluded that leadership develops in each era, but that different societies require different types of leadership. 

Keywords: leader, leadership  

The study of leadership has been conducted by many scholars. Leader and leadership are two different things: a leader is a summarizing role, and leadership is the intentional working of bringing people together. Recent studies suggest that leadership can be acquired without being acquired. 

2.1 Lewin’s Three Major Leadership Styles 

In 1939, American psychologist K. Lewin classified three types of leadership based on experiments: autocratic, laissez-faire, and democratic. He argued that democratic leadership is the most effective in terms of quality of work, willingness to work, and effective action. However, it is considered more effective to use different desirable leadership types depending on the form of the organization and its levels of growth, such as the ” autocratic type” at the beginning of the organization and the ” democratic type” when the organization has stabilized.  

classification	outline	Effective situaiton	Uneffective situation
Autocratic Style	In the short term, groups get more work done than others and can be highly productive.  In the long run, however, it is not effective, as members develop mutual animosity and distrust.	・untrained employees or groups who do not know which tasks to perform or which procedures to follow ・There are high-volume production needs on a daily basis ・There is limited time in which to make a decision	・Employees become tense, fearful, or resentful ・Employees begin depending on their manager to make all their decisions ・There is low employee morale, high turnover, and absenteeism
Laissez-Faire style	There is no cohesion in the organization, morale is low, and the quantity and quality of work is the lowest. However, this style can be effective when group members are highly qualified in specific areas.	・Employees are highly skilled, experienced, and educated. ・Employees have pride in their work and the drive to do it successfully on their own. ・Employees are trustworthy and experienced.	・Employees feel insecure about the unavailability of a manager. ・The manager cannot provide regular feedback and thank employees for their good work. ・The manager doesn’t understand his or her　responsibilities and is hoping the employees can cover for him or her.
Democratic Style	Less productive than tyrannical leadership in the short term, but more productive in the long term. It creates a friendly atmosphere among members and increases group cohesion.	・normal time ・When implementing　operational changes or resolving individual or group problems.	・There is not enough time to get everyone’s input. ・It’s easier and more cost-effective for the manager to make the decision. ・The business can’t afford mistakes. ・Employee safety is a critical concern.

2.2　Ohio State Leadership Studies 

The study was conducted in the 1950s by psychologist C. Shartle and colleagues at Ohio State University in the United States. They conducted workplace observation surveys and interviews using questionnaires that described leaders’ behaviors in detail. 

As a result, the number of leader behaviors that emerged from the observations totaled 1,700, and these were summarized as “initiating structure” and “consideration. The structural building includes actions such as setting up infrastructure and thoroughly managing subordinates’ tasks so that the organization can achieve solid results, while consideration includes actions to maintain mutual trust and better relationships with subordinates. 

2.3 Likert’s System of Management 

R.Likert proposed it by research in 1961. He regards organizations as systems and classified the management systems related to leadership into four categories “Exploitative authoritative”, “Benevolent authoritative”, “Consultative”, and “Participative”. He argued that participative makes the highest teamwork, communication, and participation.  

Exploitative authoritative	Thoroughly task oriented	・Authoritarian management methods, in which leaders do not trust their subordinates and do not allow them to participate in decision-making. ・Subordinates are forced to work through fear, intimidation, and punishment, and subsist on occasional rewards. ・Leader-subordinate interaction is rare, and control functions are concentrated at the top.
Benevolent authoritative	Task oriented> Weak relationship orientated	・Leaders trust their subordinates to a certain extent, but they have a condescending attitude toward them, like a master toward his servants. ・Leaders can make decisions at the subordinate level within predetermined limits, but most decisions and goal setting are made by the top management. ・Motivates subordinates through rewards, punishments, and hints of punishment. ・Although there is a mutual relationship between leaders and subordinates, it is patronizing and there is fear and wariness on the part of subordinates.
Consultative	Task oriented = Relationship-oriented	・The leader trusts the employees, but not fully, and the top management has the authority to make basic policies and general decisions, but individual issues are delegated to subordinates. ・Communication is two-way, and motivation is based on rewards, sometimes punishments, and some degree of involvement. ・Interaction is frequent, and a significant portion of the control function is delegated to subordinates.
Participative	Task-oriented ＜ Relationship-oriented	・Leaders fully trust their subordinates, decision-making is broadly organization-wide but integrated rather than disjointed, and communication takes place not only between superiors and subordinates but also among colleagues. ・Employee are fully involved, motivated, and ensure extensive interaction. ・Evaluation and control are complete at all levels.

2.4 PM theory  

It was proposed by Japanese social psychologist Misumi Juji in 1966. He viewed leadership from the perspective of group dynamics, in which members of a group activity are based on psychological rules. In the concept of PM, P stands for performance and represents the kind of leadership that is oriented towards the achievement of the group’s goal and problem-solving. M stands for the kind of leadership that is oriented towards the group’s self-preservation or maintenance and strengthening of the group process itself.   

pM Has the ability to organize a group, but is weak in achieving results. They are well-liked, but their work is not very good.	PM 　The ideal type that can clearly state goals, achieve results, and organize a group.
pm Weak ability to achieve results and organize a group. This is a type that disqualifies a leader.	Pm Clearly stated goals and results, but weak ability to organize the group. This type achieves results but is not well-liked.

P and M are two axes on which the level of each type can be measured (high or low), thus obtaining four distinct types of leadership. PM-type leadership that satisfies P and M to a high level improves group performance the most. 

2.5  Politics from 1930 to 1969 

The slogan of John F. Kennedy, who won the election to the presidency in 1960, was “New Frontier. New education programs and tax reductions were never approved by Congress. In foreign affairs, Kennedy was forced to walk a tightrope that included the Bay of Pigs (1961) and the Kuba Crisis (1962), and in November 1963 Kennedy was assassinated and his vice president, Lyndon B. Johnson, became president.   

2.6 Economics from 1930 to 1969 

In the 1960s, the U.S. economy experienced stable economic growth.  The economic growth policies of the time included Keynesian economic management during the Kennedy-Johnson administration. 

3.1 SL theory 

It was proposed by P. Hersey and K.H. Blanchard in 1977. It is based on the premise that effective leadership styles differ depending on the maturity level of subordinates. 

Divided into four quadrants, with the vertical axis representing work orientation and the horizontal axis representing the strength of human orientation, the chart shows how to increase the effectiveness of leadership in each situation. 

S3: Supporting  Encourage subordinates to make decisions by combining their thoughts(Leadership that is less task-oriented and more relationship-oriented) → When the maturity level of subordinates has increased further	S2: Coaching Explain our ideas and answer questions (Leadership with a high level of both task orientation and human relations) → When subordinates have increased their maturity level
S4: Delegating Delegates responsible for work execution (Leadership with minimal task orientation and minimal relationship orientation) →When subordinates have completely increased their independence	S1: Directing Provides specific direction and detailed supervision (Leadership with high task orientation and low relationship orientation) → When subordinates’ maturity level is low

3.2　 Kotter’s Leadership Theory 

It was published by Kotter in 1988. First, Kotter clarified the difference between leadership and management, emphasizing that leadership is what is needed in times of change. Management and leadership are complementary. Leadership is encouraging change in follower awareness. Management is maintaining and developing followers who are involved in the vision to achieve the vision. He also identified the most important element of leadership as “the vision of the leader,” and proposed eight stages of change to realize change. 

1	Instill a sense of crisis	Be on the alert and quickly recognize the urgency of the issue.
2	Recruit others	Form a strong promotion team
3	Create a vision	Create a vision, make it simple, and set high expectations.
4	Infuse the vision into the organization	Translate and communicate the connection between the intent of the vision and the actual work (cause-and-effect relationship) to the members.
5	Create an environment to realize the vision	Support and back up members
6	Appeal of short-term results –	Formulate a plan to achieve short-term results, reflecting the creation of a track record of execution change
7	Try & Error – Establishment of improvement results and realization of further transformation	Aim for the best through repetition, increase and develop human resources who will be the driving force of change
8	Rooting of results and sustainable development – Rooting new approaches	Rooting new approaches, passing on results to the next generation of leaders

3.3 Politics from 1970 to 1990 

The 1973-1974 oil embargo by members of the Organization of Petroleum Exporting Countries (OPEC) caused energy prices to rise rapidly, leading to shortages. Even after the embargo ended, energy prices remained high, fueling inflation and ultimately causing unemployment to rise. The federal budget deficit grew, foreign competition increased, and the stock market slumped.  

The Vietnam War lasted until 1975 when President Richard Nixon (1969-1973) resigned on impeachment charges and a group of Americans was taken hostage at the U.S. Embassy in Tehran and held for over a year. The country seemed unable to control events, including economic problems. The U.S. trade deficit widened as low-priced, high-quality imports flooded into the U.S., ranging from automobiles to steel to semiconductors. From the time he took office, Reagan based his foreign policy on the belief that communism was the enemy and that the enemies of communism were friends of the United States. For Reagan and the members of his administration, it mattered little that the groups and governments they supported were not honorable. Reagan sought to protect the country and destroy communism at the same time by strengthening the U.S. military. Reagan proposed more than $1 trillion in new defense spending to develop a ground- and space-based homeland defense shield to destroy nuclear missiles launched at the United States. However, this technological and expensive defense shield became unnecessary in 1985 when Gorbachev came to power in the Soviet Union. Political tensions between the U.S. and the Soviet Union eased, and arms control made real progress. Gorbachev’s cuts in aid to third countries and the withdrawal of Soviet troops from Eastern Europe brought about major changes in world politics. Over the course of the decade, nearly all of the communist regimes in Eastern Europe collapsed and were replaced by new democratically elected governments. 

3.4 Economics from 1970 to 1990 

The 1970s were a disaster for American economics. The recession marked the end of the post-World War II economic boom, and the United States experienced a sustained period of stagflation, a combination of high unemployment and inflation. In the early 1980s, the U.S. economy was experiencing a severe recession. Business bankruptcies rose sharply from the previous year. Farmers also suffered from declining agricultural exports, falling crop prices, and rising interest rates. By 1983, however, the economy had recovered and experienced sustained growth, with annual inflation below 5% for the remainder of the 1980s and part of the 1990s.

Leadership is largely related to the social context. Since today is called the “VUCA era” because the environment surrounding everything is becoming increasingly complex and difficult to predict the future due to the evolution of technology, the nature of leadership needs to change rapidly.