Subsidiarity relates to the division of competences, and entails decisions being taken at the most appropriate level. Complementarity relates to the use of established competences and requires that decisions taken by different participants within the field of their own powers, are consistent with each other. As the Commission has stated, there can be no complementarity if the basic philosophies, objectives and policies of the EU and its Member States diverge. Complementarity requires, moreover, that shared objectives are translated into common sectoral policies, that a common view is reached on the needs of the developing countries, and that activities are closely coordinated. Accordingly, it cannot be seen as a 'one way street' and must involve active Member State participation - with consequences for their own bilateral policies.
Complementarity thus involves a partnership of equals.
EU countries cannot force the Commission to support or participate in national schemes, although such participation is not excluded. Similarly, the EC Treaty provides for Member States to 'contribute if necessary to the implementation of Community aid programmes'. Nor does complementarity entail specialisation involving a formal division of tasks between the various actors, although one should clearly take advantage of the strengths of the different parties. What complementarity is about Despite the EU's leading role in global aid provision, the advantages of this critical mass have not so far been reaped. The results of operating largely independently have included unnecessary overlaps, work duplication and even conflicting activities.