In this essay, I will explain why power is the most important factor in international relations and why power has changed over the years, is power or is not power the main factor in international relations? There are different ways power can be defined, it cannot be classified into one area, as power is defined in many aspects. When talking about power in terms of international relations, this concept is described as very complicated as many aspects need to be considered. One definition of power in IR is that of one actor exerting influence over another, this is also known as hard power, or power can be described as having the most control over resources, for example oil, gold or food . From another point of view, power can be described as something that one state possesses and that another does not possess in terms of wealth, knowledge, etc. There are many ways in which power can be obtained, the most significant of these include military size and effectiveness, size of the state's power, technological advances and its wealth. States with these criteria would be considered a 'superpower'. The importance of power capability has changed throughout history, with one more important than the other. For example, the United States has a very advanced military power, compared to China with its technological progress and economic stability. The concept of power is mainly used by realist thinkers such as Machiavelli and Morgenthau. Machiavelli was known as an extremist realist with his famous quote from the prince “it is better to be feared than loved”. Political theorists like Machiavelli believed that power was the most important thing that moralists set aside. Realism about power is based on the relationship between state and state, as there is no general power in the world. Realism theory also states that, by not having a world government, states try to protect their interests from neighboring or rival states. Realism focuses on military power also known as hard power. However, on the other hand, liberalists believe that interaction and cooperation between states is a much more effective means than military threat. Soft power allows states to reach a compromise, in a win-win situation. An example of this is Iran coming to a compromise with the United States on the issue of nuclear weapons. Both countries are rational and open-minded, allowing lives to be saved if a war broke out.