We study optimal income taxation and public-goods provision under the assumption that the cross-section distributions of productive abilities or public-goods preferences are not known a priori. A conventional Mirrleesian treatment is shown to provoke manipulations of the policy mechanism by individuals with similar interests. The analysis therefore incorporates a requirement of coalition-proofness. The main result is that increased public-goods provision is associated with a more distortionary and a more redistributive tax system. With a conventional Mirrleesian treatment, the level of public-goods provision is not related to how distortionary or redistributive the tax system is. (JEL D82, H21, H23, H41)