Why do policymakers pass controversial immigration reforms despite widespread public opposition? More broadly, what explains the diversity of immigration and citizenship policy across countries with ostensibly similar economic interests? In this project, I address this puzzle by using a nested research design to examine the politics of citizenship reform in Europe. In the first phase of the study, I leverage a unique dataset to conduct a large-n statistical analysis across 25 European countries and 30 years in order to determine the factors that predict whether governments will restrict or facilitate access to citizenship. In the second phase, I will conduct paired case studies of two countries with historical liberal citizenship regimes (France, Belgium), and two countries with historically restrictive regimes (Austria, Germany). Within each dyad, one country has significantly liberalized its policy (Germany, Belgium) while the other’s policy regime has remained stationary or has become more restrictive (France, Austria). Drawing upon the substantial policy variation in each country since the late 1980s, I will use a combination of archival research, electoral data, and interviews with policymakers to test my hypotheses. In contrast to previous approaches, I focus primarily on the strategic preferences of policymakers. I argue that in the context of citizenship law policymakers are neither particularly responsive to public opinion nor bound by national culture; rather, they respond primarily to demographic shifts and fluctuations in the demand for citizenship. Specifically, parties will have an incentive to increase access to citizenship if they believe that the extension of suffrage to foreign residents will result in a clear electoral advantage. Conversely, parties will favor restricted access to citizenship if the structure of the welfare state or the character of foreign integration implies either substantial fiscal costs or the loss of policy leverage.