The size and the scope of government: Comparative politics with rational politicians

We try to demonstrate how economists may engage in research on comparative politics, relating the size and composition of government spending to the political system. A Downsian model of electoral competition and forward-looking voting indicates that majoritarian---as opposed to proportional---elections increase competition between parties by focusing it into some key marginal districts. This leads to less public goods, less rents for politicians, more redistribution and larger government. A model of legislative bargaining and backward-looking voting indicates that presidential---as opposed to parliamentary---regimes increase competition between both politicians and voters. This leads to less public goods, less rents for politicians, less redistribution, and smaller government. We confront these predictions with cross-country data from around 1990, controlling for economic and social determinants of government spending. We find strong and robust support for the prediction that the size of government is smaller under presidential regimes, and weaker support for the prediction that majoritarian elections are associated with less public goods.