What degree of tax autonomy should be granted to a regional government on a local tax base? Although the regional policy maker aims at maximizing social welfare, her tax policy may be distorted by the lobbying activity of local taxpayers. In this political environment we characterize the conditions under which social welfare can be increased by restricting the set of tax instruments available to the local policy maker, i.e. the degree of local tax autonomy. We show that full tax autonomy is likely to be dominated by minimal tax autonomy when there are many groups of similar size, while the converse occurs when tax bases are asymmetrically distributed.