The analysis of a temporary exhibition allows us to study how a particular project is inflected by cultural ideas (in this case also aesthetic ideas) and, above all, by cultural policies, i.e. museum practices and the socio-cultural and diplomatic contexts that explain the realization and morphology of a curatorial concept. In order to bring about an individual exhibition of exclusive works by Pablo Picasso in Mexico in 1944 a Society of Modern Art was founded, a private organization that copied the U.S. model of cultural mediation. This foundation was a product of bilateral financing by two powerful institutions, the Galería de Arte Mexicano owned by Inés Amor, and the MoMA, directed by Alfred H. Barr. Because of the political situation during the Second World War, the alliances between Mexico and the U.S. played a significant role. Based on a review of archival documentation and press articles of this period I attempt a reconstruction of the historical process of managing this temporary exhibition, understood as a spatial construction of political power in the collective imagination. This Mexican exhibition of works by an outstanding global artist has not been studied in terms of the messages and intentions conveyed by an ephemeral collection of objects that was deprived of its political anti-fascist dimension due to the exclusion of Guernica, which reduced it to an exhibition of avant-garde art. Guernica was not shown in Mexico for reasons that include U.S. anti-communism, Barr's desire to attract reflection towards the plastic values of Picasso's work and neutralize its potential for political resistance, and external conditions driven by internal struggles among Spanish Republicans.