It is common to describe the European Union as “new,” “unique,” “sui generis,” and hard to fit into existing categories of institutional arrangements, national or international. Indeed, debates on how to describe the EU are often lively and sometimes illuminating. In concrete terms, however, one of the best ways to understand the EU's distinction from other forms of treaty-based trade and integration regimes is the EU's distinctive lack of unilateral safeguard and escape valve mechanisms available to policy-makers in the various Member States.