In this Policy Paper, author Nathalie Tocci considers the concept of sustainability and how it is central to any understanding of Mediterranean politics. Too often confused with stability in policy debates in the Mediterranean region and the West, Tocci argues that not only are these two concepts distinct, with sustainability being broader and deeper than stability, but stability, as interpreted with regard to the regimes in the region, has often run counter to the very conditions that underpin state sustainability. In order to avoid the weakening and failure of EU-MED cooperation, Tocci urges the EU to overcome its political and institutional inertia, and to develop a truly credible Mediterranean policy pursued alongside other state and non-state actors at both the regional and global level. Nathalie Tocci is Deputy Director, Istituto Affari Internazionali, Rome.