Few attempts have been made to develop a systematic normative analysis of where differentiated integration may need justification, and by what standards. This contribution argues that differentiated integration should be evaluated by a standard of how far it improves the management of externalities. That standard allows for disagreement at the European level on what values best justify choices between differential and uniform integration.
Yet it is none the less a standard that member states may need to follow if they are to meet their obligations to their own publics to secure values of democracy, freedom and justice. Whether, in addition to obligations to their own publics, member states owe one another any obligations that constrain choices of differentiated integration, can then be answered by investigating how far they accord one another rights in the course of managing externalities between themselves. The example of banking union illustrates the argument.
This is an Accepted Manuscript of an article published by Taylor & Francis.