A problem that is difficult for the traditional social democratic policy to resolve is the fact that narrow limits have been set on the taxation of mobile tax bases. These limits also point to the fact that certain basic problems of economic development, which under the conditions of open market can no longer be resolved satisfactorily at the nation-state level, necessitate the harmonization of transnational regulatory systems. In the case of the tax system, measures for harmonization at the regional level of the EU are important steps in this direction. Solutions that go beyond this require longer time frames.