Recent empirical research indicates that several types of pollution seem to first increase as per capita income increases and then to decline after income becomes sufficiently high, describing an inverted U-shape that has been christened the 'environmental Kuznets curve.' Research on this topic has largely ignored the fact that pollution control is a public good, provided by government, and its level hence presumably depends on the form of government. One consequence of this is that the profession is uninformed regarding the environmental effects of political change, and can offer policy makers no credible advice on the likely environmental effects of political reform. Another is that received empirical models of the environment-income relationship are misspecified, it that they omit the form of government as a determinant of pollution levels. This can result in biased coefficients and unreliable estimates of the critical income level beyond which further growth causes pollution to decline.

The present paper seeks to remedy these deficiencies by developing a conceptual model of the environmental protection process, and the public goods provision process more generally, under different forms of government. This theoretical framework is general equilibrium in nature, and allows for international trade. It also incorporates differences in the pollution intensity of different commodities. The model thereby allows pollution to depend on a country's output mix, and allows the output mix to be affected by environmental policy. Finally, it incorporates a simple model of the political decision making process under various forms of government, ranging from pure democracy to single ruler autocracy.

This conceptual framework is then used as the basis for empirical estimation of relationships between pollution levels and income, using data from monitoring sites in a panel of countries. The same model is also used to examine provision of 'environmental public goods,' such as access to public sanitation facilities and clean drinking water. Forms of government are distinguished by identifying characteristics of government, e.g., whether chief executives are elected, effectiveness of legislatures, and degree to which party competition is allowed, that describe the degree to which government represents the interests of entire populations, rather than catering only to elite groups of rulers.