From the onset of the world economic crisis in 1929 until the end of the Second World War in 1945, artists in Europe and the Americas took positions in the struggles between parliamentary democracies, fascist dictatorships, and left-wing regimes. The single best-known artistic product of that historical moment is undoubtedly Picasso’s Guernica, which was hung in the modernist pavilion of the embattled Spanish Republic at the World Exposition in Paris in the summer of 1937....