In 1939, while Hitler was invading Eastern Europe, Neruda was appointed to manage the emigration of Spanish refugees to Chile through France. In this role, he was able to shepherd more than two-thousand refugees out of squalid camps in Southern France to Chile. It was in this work that Neruda finally shifted his entire political self-concept to that of a communist. While he was continuing to write along a socialist agenda, and while Hitler remained in control of Europe, Neruda was given the post of Consul General to Mexico in 1940. He spent the next four years in Mexico City during which he divorced his wife, lost his daughter to disease and became a staunch Stalinist.

Despondent for the loss of his daughter, Neruda returned to Chile in 1943 where he spent time becoming familiar with the folk history of Chile - with Machu Picchu in particular. He began to see connections between the ancient Incan and Mayan empires and modern day Chile that he expressed in a book-length poem of twelve parts called "The Heights of Machu Picchu" in what would become considered as one of the great political poems of the twentieth-century. In the Heights of Machu Picchu, he connects the constancy of the earth to the destructibility of life, in drawing upon the remains of the city without finding the remains of the people - "Thrones toppled by the vine. / Regime of the entangled claw." (Canto 9). In so doing, he also called attention to the constancy of the people - the constant need for the farmers, the laborers, and all those that make society function - without whom life would cease to work.

When, in 1945, Stalin defeated Germany along the Eastern Front of the war, he became an icon that would be central to Neruda's life and politics for several decades. The left-leaning literati and philosophers of Chile came to greatly admire Stalin for his achievement of not only bringing victory to the Soviet Union over Fascism, but also to the realization of Lenin's goals of creating a communist state.