Europe's ambition for a unified labour market is as old as the Treaty of Rome. This ambition is arguably older and stronger than the hope to unify goods, services and capital markets in Europe. Despite this long and concerted effort, Europe still lacks an overarching approach to labour market unification. There are no comparative studies that examine labour market integration in other states and no commissioned reports focused on the costs and benefits of creating a common, continental-sized, labour market. We still lack a theory of optimum labour areas.

Europe's approach to capital market integration could not be more different. In 1999, the EU began a grand social experiment: it wanted to integrate once national money markets into a common European currency. To do so, policymakers drew from a broad-based and established literature on optimum currency areas (OCAs) and academics studied previous experiments with monetary integration (for example, in the US, the Latin Monetary Union, the Scandinavian Monetary Union) to anticipate the potential costs and benefits of jettisoning local currencies in exchange for the euro. Numerous studies were conducted by public and private research groups, with an eye to gauging the costs and benefits involved. While it is possible to argue that the advice generated by this vast literature was not heeded, no one doubts that it was desirable, necessary and relevant.

This difference in approach is remarkable and difficult to understand. After all, many believe that the integration of labour markets provokes more political and social turbulence than the integration of capital markets. As we saw in Chapter 2, labour is more than a commodity exchanged at market: it is a fictitious commodity, held by family members, friends and citizens – each of which maintains social and political obligations that extend beyond the marketplace. It is because of labour's unique qualities that labour markets are the most regulated and politicized markets in modern economies. The integration of these markets affects not only the buyers and sellers of labour power, but also the larger bundle of rights and opportunities associated with national social models. For all these reasons, we might expect to find more discussion about what kind of common labour market Europe hopes to create.