The international relations schools of thought known as Realism and Idealism identify specific and similar characteristics of actors in the conceptual development of their theories. While many of these characteristics can be generalized as being synonymous between the two theories, both theories make a separate distinction in what specifically constitutes an actor. In Realism, the term “actor” refers directly and solely to the state: a combination of government, leaders, decision-makers, etc, that act as a unitary entity to promote the interests of the state. Idealists however expand on what constitutes an actor to include both the state and people. Not only do the principles of Idealism assert that the state and people should be considered actors, in fact both they must be viewed as actors. Actors have interests; while realists such as Machiavelli insist the state is the only unit of analysis necessary in international politics, idealists argue that just as states have interests, people in government have interests as well. Therefore, Realism and Idealism begin their assessment of actors from two different perspectives however both schools of thought go on to identify many characteristics of actors which are largely similar. For both realists and idealists actors are autonomous; they exist independently and retain sovereign rights over material and non-material resources. In both Realism and Idealism actors are said to possess prioritized interests and preferences. While the two schools of thought emphasize a separate, ultimate “desire” of actors, both theories imply that actors pursue their specific interests or desires rationally. Furthermore, in both Realism and Idealism actors are said to be equal and enjoy an equality of opportunity in the political spectrum under which they operate. Both theories approach this idea of equality from a perspective of legal status: as states both Russia and San Marino possess the same legitimacy in the international order; as individuals, no one person’s vote can count more than another.
Another concept the theories of Realism and Idealism share is they both recognize a singular issue as the key problem in international relations. For both schools of thought it is the competition over a limited availability of resources that is the overriding problem international relations must address. Resources can include everything from raw material deposits, military hardware, educational levels, organizational capacities, population levels, etc. In other words, resources are anything that can be brought to bear which further the interests of states-actors. In fact, the finite nature of resources can be directly linked in both theories to motivations that determine the actions of actors and to the creation of the environment actors operate in. In both Realism and Idealism the aggregate of an actor’s actions, or the accumulation of those actions, is what determines the actor’s environment. On the surface this appears to be a paradoxical principle, in that one’s environment could be said to influence one’s actions, but in turn those actions are said to be what spawns the atmosphere the actor engages in. However when viewed through the spectrum of a supply-demand analogy one can see how the combination of an actor’s actions along with the availability of resources establishes the international political environment of the entity. In Realism and Idealism actors have interests which they pursue rationally. Even though the ultimate desire expressed in both theories is different, they are both striving for the maximum realization of that ultimate desire. Thus the demands of the states/individuals paired with the available supply of resources/values determine the actions of actors in their pursuit of their desires. The point at which the aggregate demands of the actor meet the aggregate availability of resources is what creates the environment.
While both Realism and Idealism identify competition over limited resources as a key issue state-actors must overcome, they differ significantly in their interpretations of the meaning and ramifications of competition. For realists such as Morgenthau, the availability of resources is related to the distribution of power between states. Resources are limited because states’ primary interests are power and national security; in order to further these interests states are constantly striving to amass resources. Resources have a finite availability however and at some point states can only acquire more resources by taking them from some other state. This constant division of the worlds’ resources determines the relationships between states: competition is fierce, long term cooperation isn’t possible, and the inevitable outcome is eventually war. While idealists such as Mitrany also view the unequal distribution of resources as the primary cause of war in international relations, Idealism does not hold war as an inevitable outcome of competition. One of the principle reasons for this is that idealists believe state cooperation is not only possible but is in fact a normal function of international relations. Proponents of Idealism recognize the limited nature of resources but they also see a potential for growth that realists do not identify. Idealists envision a world in which resource levels could increase through advancements in technology, the opening of new free-markets across the globe, and the expansion of representative governments which provides individuals more opportunities to pursue their own interests. Idealism stresses that actors are capable of rationally recognizing shared common interests and acting in a spirit of mutual cooperation to better facilitate the realization of those interests. Long term cooperation is established through the creation of alliances and the promotion of trade. As Kant explained in Perpetual Peace, when states engage in commerce, or other policies which promote mutual benefits, the result is increased levels of cooperation and fiscal returns. Increased cooperation begets increased profits, leading state-actors fewer reasons to allow competitive conflict to interfere. In other words cooperation leads to increased levels of peace. Ultimately, according to Kant, state cooperation would spread throughout the international system leading to development of a "spirit of commerce" that is "incompatible with war."
While Realism and Idealism share a few generalized components in the construction of their respective theories, it is the differences found in the schools’ theoretical conclusions that truly set them apart from one another. This is profoundly identifiable when one examines specific contrasting principles that lead the two theories to draw vastly different conclusions centered on the possibility of peace in international relations. Two of the most important contrasting elements of Realism and Idealism is how the two theories conceptually prioritize the interests of the state-actor and the manner in which the two theories view the “state of nature:. Realists uphold the pursuit of power as the singular, overriding interest of the state. Realists view the non-political world as one that is incomprehensible due to the various desires of individuals and sub-state groups. Furthermore the world is not a nice place, as Hobbes described it, humanity without government lives in a state of “continual fear and danger of violent death, and the life of man, solitary, poor, nasty, brutish, and short.” In such an environment of confusion the world exists in a state of anarchy that according to Hobbes was a “war of all against all.” To the realist then order is based on power, everything else is uncertain. The realist Machiavelli pointed to the history of international relations to support this idea that a states overriding concern was the advancement of power, while Hobbes upheld power as the eminent characteristic of human nature. If state leaders have a natural tendency to constantly pursue their interests of power, competition and conflict is seen as normal but also necessarily violent and fierce. Therefore the establishment of a large standing army is necessary to ensure the survival of the state. War is inevitable as states seek to empower themselves by acquiring vast amounts of resources that are limited in number, war is also the way manner in which the balance of power is necessarily determined.
For idealists however war does not originate from one’s natural tendencies to acquire power, instead idealists see states organized around power politics as being responsible for creating an environment that facilitates warfare. Unlike realists, idealists identify other interests that propel human nature. In particular, Idealism holds the pursuit of wealth and the desire for peace as being just as important in influencing the actions of state-actors. The pursuit of wealth and the desire for peace in turn promote state cooperation and in this way, progress towards an increasingly peaceable world can be achieved.