Anonymous. (2026). Pre-algorithmic confounders including homophily, partisan identity strength, and cable TV are documented to be quantitatively larger contributors to polarization than algorithmic ranking in available studies, though their precise share of post-2012 growth is not established. Isonomia. https://www.isonomia.app/a/wCV7c6Mn@5442e93f1a84bf0983fe5b6443d6624c2c14314262d64bf0279772e976b229d9