Anonymous. (2026). Boxell et al. (2024) explicitly identify US-specific non-algorithmic factors as the best explanation for US polarization divergence, not merely the presence of social media. Isonomia. https://www.isonomia.app/a/Tl1IW1cz@b2134728f614e45175db1a43f9f03c6b4c97e909848d3be6e4b53d9277f85497