Computational Analysis of 140 Years of U.S. Political Speeches Reveals More Positive but Increasingly Polarized Framing of Immigration; Leah Platt Boustan (Princeton University)

Abstract
We classify and analyze 200,000 U.S. Congressional speeches and 5,000 Presidential communications related to immigration from 1880 to the present. Despite the salience of anti-immigration rhetoric today, we find that political speech about immigration is now much more positive on average than in the past, with the shift largely taking place between WWII and the passage of the Immigration and Nationality Act in 1965. However, since the late 1970s, political parties have become increasingly polarized in their expressed attitudes toward immigration, such that Republican speeches today are as negative as the average Congressional speech was in the 1920s, an era of strict immigration quotas. Using a novel approach based on contextual embeddings of text, we find that modern Republicans are significantly more likely to use language suggestive of dehumanizing metaphors when discussing immigration, such as Vermin and Machines, and make greater use of frames like Crime and Legality.