Change in the approach of great powers towards Latin America and also change in the nature of their relations with regional countries have brought about major shifts in their diplomatic actions. The main question posed by this article is that have these changes led to a competitive diplomacy among great powers including the United States, China, Russia and the European Union? If so, what are the main components of this pattern and how could it be explained and analayzed? To answer the main question, this article puts forward the hypothesis that under present circumstances, due to the transition of world order towards a multi-polar system and the decline of the U.S. power, this country has lost its extensive influence on Latin America. Therefore, the most important US rivals have seized the opportunity to reinforce their economic and military presence in Latin America. Given the nature of this article, investigating the formation of a new pattern regarding diplomatic competition among great powers in Latin America requires addressing scientific indices of international relations discipline and its combination with the art of diplomacy. For this reason, first we explore and compare the theoretical foundation and regional diplomatic strategy of great powers in Latin America by using the method of analysis and comparison and then we evaluate the pattern competition among great powers relying upon some indices such as statements, positions taken by officials, actions, decisions, etc. In this analysis, the formation of competitive diplomatic pattern of great powers in Latin America is considered a dependent variable which is the function of independent variables such as the decline of U.S hegemonic power, strategic interests of great powers, transition period of international relations, and charcteristics of regional countries
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