Latin American allegiances in World War I were complex, often reflecting the heterogeneous ancestry of their migrant populations. However, the hardships caused by the German shipping blockade of the Atlantic caused rising resentment, and left the US the dominant trading partner and power-broker in the region. The tipping point came with the US entry to the war on the Allied side in April 1917; Cuba and Panama immediately followed suit. Barring neutral Mexico, the rest of Central America had committed to the Allies by September 1917. South America was more nuanced; Brazil was the only country to enter the war with the Allies, the rest split between neutrality and severing diplomatic relations with the Central Powers. Post-war the Latin American nations enrolled in the League of Nations. However, its credibility was undermined by US’s failure to join, and many subsequently withdrew before the organization’s demise in 1946.