This paper develops a positive theory of pollution taxation by a federal authority when pollution abatement subsidies are used by local governments. Environmental and industry lobby groups influence governments with campaign contributions. First, pollution may increase in the pollution tax because the abatement subsidy increases (decreases) with the tax, and pollution increases (decreases) in the abatement subsidy. This occurs because the lobbying incentives change at a pollution tax reform. Second, pollution taxes may reduce net revenues because subsidy expenditures rise. Third, pollution may increase simultaneously as net revenues fall. Finally, the welfare effect of a pollution tax may be negative.