This article exploits two newspaper archives to track economic policy uncertainty in Spain from 1905–1945. We find that the outbreak of the Civil War in 1936 was anticipated by a striking upward level shift of uncertainty in both newspapers. We study the reasons for this shift through a natural language processing method, which allows us to leverage expert opinion to track specific issues in our newspaper archives. We find a strong empirical link between increasing uncertainty and the rise of divisive political issues like socio-economic conflict. This holds even when exploiting content differences between the two newspapers in our corpus.