The Political Significance of the "Second Demographic Transition"(SDT) in the U.S. : A Spatial Analysis

Ron J. Lesthaeghe, University of Michigan and University of California, Irvine
Lisa J. Neidert, University of Michigan
Didier Willaert, Vrije Universiteit Brussel

To what degree can political outcomes at the level of counties be predicted on the basis of the new patterns of household formation, commonly referred to as the "Second Demographic Transition" dimension (SDT)? Dependent variables are: Presidential election of 2004, same sex marriage amendments in 24 states (2004+), and the 2006 Missouri stem cell referendum. The SDT predictor is the principal component of several indices related to marriage and parenthood postponement, subreplacement fertility, and cohabitation. Controls include socio-economic variables (income, education, urbanity), cultural variables (percentages Evangelical/Mormon and Catholic) and ethnicity (percentages Black, Hispanic). The spatial correlations between the voting outcomes and the SDT-dimension are strikingly high and resistant for ALL controls. This suggests that the spatial differentiation according to household formation is a significant and non-redundant predictor of political outcomes particularly when related to the so called "Culture War." Color maps available on www.sdt.psc.isr.umich.edu/ Both convential maps and Gastner-Newman cartograms.