While the effort within the state politics literature to isolate the p
olitical determinants of public policy represents one of the most succ
essful research programs in political science, researchers have in the
main failed to consider the special role of labor organization in a c
apitalistic democracy. Using cross-sectional and time-series data on a
number of policy indicators, we demonstrate that the relative strengt
h of the labor movement across the American states is one of the princ
ipal determinants of policy liberalism. The implications for public po
licy and the study of American politics are discussed.