Determinants of Political Polarization and Consensus in the US Congress: An Analysis of Policy Issues and Institutional Factors (1991–2020)

ABSTRACT This study examines how different policy issues and institutional factors influence the strength of political consensus and polarized voting in the United States (US) Congress between 1991 and 2020. Utilising the Jordan Tama important congressional votes dataset, the analysis investigates the impact of external factors, such as foreign trade, immigration, domestic policy, spending, military/security issues and presidential position, as well as internal factors, such as divided party control. Our analysis employed descriptive statistics for all variables, pairwise correlation, ordinary least squares (OLS) regression, binary logistic regression and marginal effects modelling to estimate predictors. The results indicate that immigration and domestic policy issues significantly reduce consensus and increase polarization, while spending bills foster greater bipartisan agreement. Presidential involvement and periods of divided‐party control emerge as strong predictors of polarized voting, whereas foreign trade and international finance do not significantly alter underlying partisan and consensus dynamics in both houses. The findings contribute to partisan and electoral theories by demonstrating how specific policy domains and institutional dynamics interact to shape legislative outcomes in the contemporary polarized political environment. The study highlights challenges facing efforts to restore legislative functionality and the foundational role of compromise in American democracy.