Are cities beginning to articulate a distinctive agenda in international affairs, one that sets them apart as diplomatic actors in their own right? A growing body of opinion thinks so (Attwell, 2013; Calder and Freytas, 2009; Tavares, 2013; van der Pluijm, 2007). Yet the evidence points to an uneven evolutionary process, the analysis of which has been further clouded by an array of new terms and ideas posited by enthusiastic commentators. In a recent Foreign Affairs article, Rodrigo Tavares, international relations head for the Sao Paolo state government, describes how sub-national governments around the world are articulating external relations agendas that are distinctive from their national contexts and which focus on the nuts and bolts of promoting their regional interests (2013). Of course, the idea of nimble, confident city-regions forging practical partnerships to solve problems while lumbering nation states struggle to achieve traction on a range of issues, from Syria to climate change, has intuitive appeal. There is also much truth in this narrative. A real-world example is the recent trade deal signed between Chicago and Mexico City, which sets out an ambitious economic partnership involving joint initiatives in trade, innovation, education, industrial expansion and enhanced global competitiveness (Liu and Donahue, 2013). What makes it intriguing is that the agreement is tailored to the economic interests of each partner city, rather than, say, following the instructions of some broad geostrategic agenda defined at a federal level. It goes far beyond a ‘sister cities’ pact to stipulate specific programs aimed at enhancing the $1.7 billion in locally produced trade that flows between the two metropolitan areas.