In May 1942, Mexico made a pivotal decision to align itself with the Allied Powers during World War II by declaring war against the Axis Powers. The declaration followed the escalation of German submarine activity in the Gulf of Mexico, particularly the sinking of two Mexican oil tankers, the 'Potrero del Llano' and the 'Faja de Oro.' These attacks galvanized public opinion and prompted the Mexican government, led by President Manuel Ávila Camacho, to support the Allied cause. This decision was not only a military move but also signified Mexico's desire to assert sovereignty and foster greater international cooperation in response to aggression.

President Ávila Camacho's administration underscored the importance of defending democracy and freedom, which aligned with the broader principles of the Allied nations. Following the declaration, Mexico contributed primarily through economic support and military cooperation, becoming an important supplier of resources, including oil, to the United States and other Allies. However, it was also a complex period for Mexico, as the government had to manage domestic issues while participating in the global conflict.

The war would lead to increased militarization in Mexico and foster a sense of national identity, as citizens rallied around the cause. Additionally, the United States and Mexico would strengthen their diplomatic ties, leading to various agreements to facilitate cooperation. Throughout the war, Mexican pilots joined the fight in the 'Escuadrón 201' and were integrated into Allied operations, showcasing Mexico's commitment to the international war effort and paving the way for post-war collaboration in both military and economic spheres.