Immigration Clashes, Party Polarization, and Republican Radicalization: Tracking Shifts in State and National Party Platforms since 1980

Studies of U.S. politics increasingly aim to make sense of two key trends: party polarization and Republican Party radicalization. Surprisingly, however, party divergences on immigration have been largely overlooked. Drawing on state and national political party platforms since 1980, we document the rise of attention to immigration, the polarization of substantive party positions, and the sharp GOP turn toward restrictive measures. After pinpointing the timing and relative trajectories of national and state-level agenda shifts, we explore potential drivers and establish two sets of flashpoint events worth further study: highly visible and mostly deadlocked congressional battles over immigration grand bargains, and bottom-up reverberations from the widespread 2006 immigrant rights protests and post-2008 Tea Party organizing. We find that grassroots Tea Party efforts were intervening accelerators rather than original causes of the Republican embrace of tough immigration restrictions. The article concludes by stressing the chronological layering of successive party polarizations—from 1960s divergences around civil rights, through clashes about abortion and LGBTQ rights from the late 1970s to the 1990s, and followed by immigration polarization in the 2000s. This process of layering polarizations on top of one another may have supercharged recent GOP turns toward ethnonationalism and tolerance for threats of violence.