Brazil's decision to leave the League of Nations was driven by various factors related to its political ambitions and dissatisfaction with the organization itself. Founded after World War I to foster peace and cooperation among nations, the League struggled to maintain cohesion, particularly as major powers like the United States chose not to join or support it fully. Brazil had been a founding member of the League and participated actively in many of its discussions. However, over time, it became increasingly apparent to Brazilian leaders that the League was failing to address pressing global issues and that it was unable to prevent conflicts, undermining its original purpose.

In the years leading up to this decision, Brazil's foreign policy began to shift towards a more assertive stance in Latin America. Influenced by regional politics and the rise of nationalism, Brazilian officials like Foreign Minister Oswaldo Aranha sought to cultivate stronger ties with neighboring countries while distancing from the League's often Eurocentric agenda. As Brazil confronted diplomatic tensions with other member states and grappling with issues of sovereignty and influence, the sense of frustration grew, culminating in this significant announcement.

The removal from the League was not merely an act of defiance but a calculated move towards a broader vision of regional leadership. Brazil aimed to redefine its role in international relations, emphasizing cooperation within Latin America through initiatives such as the Pan-American Conferences, rather than relying on a League that seemed ineffective. This transition laid the groundwork for Brazil's subsequent foreign policy actions, especially as it moved closer to the United States and other regional powers in the ensuing decades.