Historical Polarization in Legislative Support for Civil Rights in the United States

Sixty years after the civil rights movement, we examine the historical trajectory of civil rights through the language of US legislation. Using natural language processing (NLP), we find that civil rights has become a more common but also a more polarized policy area. Polarization between Democrats and Republicans accelerated during the early 1990s and the mid-2010s. The latter acceleration coincided with the rise of the “Black Lives Matter” movement, and it was driven by a surge of legislative support for civil rights among racial minority Democrats. Content analyses show that civil rights legislation supporting racial minorities, women and the LGBTQ+ community has polarized most, while legislation supporting the elderly and disabled has declined in both parties. Our findings offer new insights into party polarization, race and ethnicity politics, and collective action tipping points. We showcase NLP as a valuable method for studying the changing behavior of political elites.