This article focuses on the concept of “foreign policy costs” of great powers based on Paul Kennedy’s theory on “the rise and fall of great powers” and examines their impact on the evolution of power in international relations. The foreign policy of great powers is costly, depending on the claims and commitments they have made. They expect benefits in return for their foreign policy costs. The main question of the present article is what effect does increasing foreign policy spending have on the survival of the great power position? The initial answer is that although the increasing trend of foreign policy costs relative to foreign policy benefits facilitates the decline of the great power position and the great powers' shift, the mechanism of the impact of spending on power is much more complex than that proposed in Kennedy’s theory. This article seeks to provide a relatively comprehensive analysis of the theory's strengths and weaknesses.
 
Materials and Methods
Some of international relations theorists, focusing on the material dimensions of national power in international politics, have spoken of the cyclical shift of great powers. One of the famous researchers in this field is Paul Kennedy. This article considers the important criticisms of Kennedy's theory and then attempts to present, through a qualitative method, a more comprehensive analytical framework regarding the rise and fall of state power in the present era.  
 
Discussion and Results
In a great study, conducted on the interaction of economic capabilities and military strategy of great powers from the sixteenth to the late twentieth century, Kennedy emphasizes the concept of "imperial overstretch" as the driver of the power cycle. In the process of the rise, growth, and decline of great powers, there is a clear connection between "economic rise and fall" and "military rise and fall." Although economic and technological power alone have not determined the course of changes, their role in the rise and fall of countries has been critical. While introducing the United States as a superpower doomed to decline, Kennedy advises its officials to accept current realities and avoid futile conflicts, and to manage affairs in such a way that the relative erosion of the country's position occurs smoothly and slowly. He adds that one of the current global trends is the development of the Pacific region, which is likely to persist in the future and seems to shift the center of gravity of the world economy towards Asia and the Pacific. Kennedy writes about China that if the current process of China's development continues, its position will change within a few decades. Although the country faces weaknesses such as low technology, there are interesting signs about China's reform and self-improvement. Kennedy's theory has faced various critical reactions. The first point is that the idea of ​​a destiny of decline is along with a kind of determinism in social changes. When decision-makers realize that their decisions will lead to mainly negative and destructive results, they can correct them. Second, Kennedy's view of the process of world economic changes is not comprehensive. Kennedy does not attempt to analyze the driving forces of economic growth and development during the last 500 years of history, and this could seriously damage his main thesis. The third is the lack of attention to the non-economic dimensions of military capability. For example, coalition-building diplomacy has a great impact on military and geopolitical capability. The fourth criticism is the reduction of power to hard economic and military elements. Other factors, including the capability of the political system, the genius of decision-makers, social values, and identity potential, are underestimated. The fifth criticism is the incomplete narrative of historical developments. Kennedy, for example, does not explain why Habsburg Spain lost its powerful position in Europe and the world and withdrew from the scene of great power competition, but France and Britain still remaining as great powers of the world. The final point is that the costs of foreign policy are manageable. It is possible to reduce the costs of foreign policy while strengthening soft power.
 
Conclusion
The essence of all criticisms is that Kennedy's theory of the power cycle has not seen some important and influential variables influencing power shifts, including soft power components.  Despite these points, Kennedy's theory still has a wide influence in academic circles, and its alarming effect on the foreign policy decision-makers seems undeniable. Decision-makers in great powers have more or less come to the realization that, although military and economic strength facilitates the pursuit of national goals and interests in the world, it may not be sufficient to compensate for major costly foreign policy mistakes. Power may even have a misleading effect, inciting states to make decisions whose destructive consequences for national interests far outweigh the expected benefits. The exorbitant and increasing costs of foreign policy projects can push a great power toward decline and submission to the emergence of an alternative great power. States sometimes realize the costs of their decisions when there is no way back.