In this paper, we examine the events leading up to the United States’ asset freeze on Japan in July 1941 and its evolution into a comprehensive embargo. We also analyze the perspectives of US government leaders regarding oil exports to Japan. This analysis aims to assess whether there was a significant gap between policy decisions and their implementation, as commonly believed. Additionally, since the effective implementation of the oil embargo against Japan necessitated cooperation from other oilproducing countries, such as the United Kingdom and the Dutch East Indies, we explore the discussions among these nations and the process for enacting a joint embargo against Japan. Through this examination, we aim to understand the execution of an economic sanction expected to elicit a strong response from Japan, like the oil embargo, and to discuss its political and diplomatic consequences. Prior to the implementation of Japan’s asset freeze as a full embargo, there was a gradual evolution of policy over approximately two months, conducted in close collaboration with allies, namely the United Kingdom and the Netherlands. This cautious approach to imposing economic sanctions on Japan was driven largely by concerns over a potential Japanese retaliation to a sudden oil embargo. It can be argued that US policymakers, including Dean Acheson, advanced cautiously towards an oil embargo, carefully monitoring Japan’s response to the sanctions and striving to secure the support of crucial allies. This approach, contrary to popular belief, suggests that policymakers such as President Roosevelt and Secretary of State Hull provided indirect or tacit approval for this measured process, rather than their intentions being overlooked in the policy’s actual execution. Therefore, the US-led oil embargo initiated in late July 1941, in reaction to Japan’s occupation of southern French Indochina, should be understood as the culmination of an international and domestic consensus that had been forming over an extended period within the US government and in consultation with countries like the United Kingdom and the Netherlands. This perspective offers a more nuanced understanding of the global strategy agreed upon by the United Kingdom and the United States in August 1941 and the historical context of the United States’ entry into World War II. Recognizing that the divergent positions of the United States and Japan on the eve of the Pacific War were irreconcilable through diplomacy, and essentially constituted a clash over their visions for East Asia’s future, is crucial.