Photo by Dan Eaglesham, Flicker Creative Commons

By Benjamin Leffel and Michele Acuto

Imagine a football game. The majority of those in attendance are in the stands, mere spectators to the game being played on the field before them. Populating the field are the few: the designated uniformed players, referees, and coaches—an apt metaphor for “traditional” diplomacy. In centuries past, world affairs have been conducted by designated national-level players—heads of state, diplomats, ambassadors, and so forth—while the remaining majority, the vast populations and local leaders representing them, look on as spectators. However, the globalizing forces of the latter half of the 20th century have brought those who once were mere spectators to world affairs—local leaders—onto the field as new and often very effective players.

It is from this context that “city diplomacy” has emerged: city government leaders, on an individual or collective basis, have progressively been engaging in social, political, and/or economic activity aimed at achieving outcomes beyond their own jurisdictions. Tangible evidence shows that city diplomacy in its modern form has been occurring for over a century, but much more clearly observable is the accelerated city diplomacy that has taken place over the past three decades, which showcases city interactions whose impact spans not only a domestic, nation-wide scale, but also a transnational scale reaching beyond the borders of nations. A playing field once exclusive to nation-state actors now is significantly more populated with mayors and other city leaders, making the “game” of diplomacy itself more complex. The study of city diplomacy seeks to discern order from the seeming chaos of this diplomatic playing field now flooded with new and non-traditional actors. It also questions whether the game is in fact much bigger and much more complicated than what we’ve long thought, spanning a multitude of fields across the whole public-private spectrum of global governance.

City diplomacy is not (yet) equivalent in its power to bring about political-economic outcomes as traditional diplomacy. It is often used to assist nation-states to better achieve a range of goals, as was the case under the Clinton State Department’s creation of the Office of the Special Representative of Global Intergovernmental Affairs, to which Secretary Hillary Clinton appointed Reta Jo Lewis as special representative. Lewis then carried out multiple commercial, capacity building, and other interactions between U.S. subnational governments and multiple other countries.1

City diplomacy has also been used to counterbalance actions of the federal government, from the Cold War-era global nuclear free zone movement to sanctuary city movements in the United States—those providing safe-haven to Central American refugees in the 1980s and those doing the same for Syrian refugees (and others) today. Further still, city diplomacy is used to fill the void of nation-state leadership in global governance issues: City governments organize into Transnational Municipal Networks (TMNs) like C40 Cities Climate Leadership Group (C40) to improve urban capacity to flight climate change and coordinate global urban efforts to that end. A common mistake has been to think of the global phenomenon of city diplomacy as a force undermining or even attempting to supplant the nation-state. In reality, city diplomacy represents increased collective capacity to solve a range of problems spanning the local and global levels.

In the age of Brexit and Trump, city diplomacy becomes particularly relevant in filling the void of the nation-state leadership and does so in distinctly economic and political terms. The following two sections describe the relevance and context of city diplomacy as it pertains to economic issues of the sort brought about by Brexit, and as it pertains to the political issues of the sort incurred by U.S. President Donald Trump.

Brexit, the Global Economy, and City Diplomacy

City diplomacy exists on a political-economic foundation. The global expansion of productive processes following the end of the Second World War saw cities become the primary sites for transnational capital inflows and outflows. The post-1970s rise of neoliberal trade and relative fall in protectionism accelerated this process, drawing cities directly into world markets, as nation-state intermediaries to the global economy became increasingly obsolete. Advances in and global spread of information communication technology in subsequent decades combined with increased urban global economic competitiveness resulted in a significant improvement in the foreign affairs competency of cities.2 The national governments of different countries grant varying levels of autonomy to locales for participation in foreign affairs, but foreign commercial engagement is generally acceptable.3 Equally, coalitions based on proactive agendas that, at least throughout the 1990s and 2000s, do not directly undermine state sovereignty have faced similar reactions—with environmental and climate campaigning by the likes of Local Governments for Sustainability (ICLEI), United Cities and Local Governments (UCLG), and C40 Cities being prime examples.

Economically, the label of a “global city” is an increasingly desirable title for many cities around the world for marketing purposes.4 City government leaders in recent decades also have used myriad means to attract investment and promote exports and tourism, such as by establishing trade representative offices abroad, leveraging sister city connections, and other forms of formal and informal economic networking. City diplomacy of the commercial variety, then, can be understood as the use of such foreign affairs competencies to maximize the competitiveness of cities in the global economy. This does not mean that city diplomacy lacks cultural, environmental, or other traits, but rather that many of the drivers that spur(red) city diplomacy in the late 1990s and early 2000s are of a political-economic nature.

It was clear to early city diplomacy scholars in the late 1980s that potentially negative political reactions to the very globalized trade liberalization that brought cities such economic prominence could have a powerfully negative impact on the cities of the world.5 This is true today in Europe, as the member nations of the European Union (EU) suffer the economic consequences of the protectionist-inspired exit of Britain from the EU, or “Brexit.”

That cities today are both the principal sites for transnational capital flows and have the capacity to directly compete in the global economy begs the question: Can commercial city diplomacy in European cities help slow the negative economic impacts from Brexit, or mend broken economic linkages? Whatever the answer, it is clear that the strength which European nations hold in the global economy is such that negative economic shocks experienced in that region will be felt the world round.

Trump, Political Leadership, and City Diplomacy

A key bit of wisdom often repeated by practitioners and scholars of city diplomacy is that while cities cannot enter into treaties with foreign entities, they can do virtually everything else: sign memoranda of understanding with foreign governments, make binding and non-binding political declarations and resolutions, and organize to form new bodies and influence virtually any social, political, and/or economic matters under the sun. Much as with the multilateral nature of inter-national relations, cities around the world network with one another to negotiate and achieve a range of sought-after goals. This points to the fact that, while perhaps not on the (multilateral) field where national diplomats have been playing, cities have nonetheless engaged in the “game” of global governance for quite some time now. There are many examples of city diplomacy playing a role in these activities, from the Mayors for Peace campaign, to C40’s advocacy for the Paris Agreement and local action beyond states on climate change. City diplomacy even reaches into the domains of health, security, and cultural relations.

Beyond the exchange of economic flows such as capital described in the previous section, cities also network in ways that can be typified as political, as in diplomatic or quasi-diplomatic functions, people-to-people or cultural exchanges, and social flows such as foreign aid.6 As a result, city leaders in the past three decades have increasingly identified with the global community, claiming political authority in foreign affairs with growing frequency.7

It is through these capacities that cities take counterbalancing action to national government mishandling of foreign or domestic affairs when deemed necessary. The criteria for “necessary” most often involves conditions in which federal government action, or lack thereof, negatively impacts the safety, health, or otherwise well-being of a domestic, foreign, and/or global population.

The crowning example of city diplomacy during the Trump administration thus far is President Trump’s decision to withdraw the United States from the 2015 Paris Agreement on climate change, which resulted in several hundred cities and several states committing to enforce the Accord in the federal government’s absence through a new body called the U.S. Climate Alliance. In so doing, American city and state leaders filled the void of political nation-state leadership left by Trump’s withdrawal.

A more institutionalized means of “counterbalancing action” is the ability for individual subnational entities to pose legal challenges to federal governments, which is slightly beyond the purview of city diplomacy, but can be efficacious nevertheless. This year, several U.S. states posed legal challenges to President Trump’s temporary travel ban from seven majority-Muslim countries, followed soon thereafter by higher courts blocking the ban. The city of San Francisco sued the Trump administration for its executive order seeking to penalize sanctuary cities, resulting in a higher court halting the executive order.

The city diplomacy embodied in the U.S. Climate Alliance has strong historical precedent.  During the 1980s, President Reagan fought the Cold War in part by shifting federal funds away from local aid and toward the defense budget. Reagan also funded anti-communist forces in Central America, leading to civil war and death, and the U.S. federal government also collectively failed to sufficiently penalize South Africa for continuing apartheid. This resulted in direct U.S. city-level intervention in all of these areas and more, in what came to be known as the “municipal foreign policy movement.”8

This points attention to the criticality of the networked topography of city diplomacy. Much as today’s U.S. Climate Alliance is an organized network of subnational entities, the cities of the municipal foreign policy movement of the 1980s advanced several causes by forming networks, thereby increasing their capacity to take action. As chronicled in newly available digital archives of the former Center for Innovative Diplomacy, in the early 80s, then-Irvine, California, Mayor Larry Agran established a national network of local officials advocating for nuclear disarmament called Local Elected Officials for Social Responsibility (LEO-SR), which merged with a similar network called the Center for Innovative Diplomacy (CID).9

Together, CID and LEO-SR grew to a network of over 6,000 U.S. local officials and activists engaged on virtually every city diplomacy issue of the time, arming cities with such information as model ordinances for sanctuary cities, nuclear free zones, and apartheid divestment action, and convening cities to that effect.

As thousands of cities from around the world advocated nuclear disarmament by establishing Nuclear Free Zones (NFZs), they organized and met at several annual international conferences on NFZs. When one of these conferences was held in Oregon, attending American city leaders established the U.S. Nuclear Free Zone Association to further network domestic efforts and thus bolster NFZ efforts nationwide.

Similar city diplomacy networking efforts took place in other issue areas: The Central American Sister City Task Force formed by several mayors to better coordinate the sending of aid to embattled Central American communities, and the U.S.-South Africa Sister Community Project formed to similarly help better coordinate efforts by U.S. cities to both divest from South Africa and to assist suffering black communities.10

It has been on this historical foundation of city government and civil society leadership that American city diplomacy of today has developed, and has shown this year that it continues to stand at the ready—particularly in light of the networked efforts among subnational entities to form the U.S. Climate Alliance. If the capricious political leadership of President Trump yields yet more voids of political leadership, city diplomacy and associated network formations acting as a counterbalance can be expected in response.

Global Governance and City Diplomacy

In the nation-state centric framework for global power that Hans Morgenthau put forth in the 1940s, subnational entities had no role—but he was not writing in a time when most of the world’s population lived in cities, as is the case today.11 It is because of this massive demographic shift that the global population now articulates itself through cities—hence the oft-repeated label of the 21st century as the “century of the city.” The governance issues faced by city government leaders are now the concern of most of the world’s population, and necessarily become a global governance issue.

Global governance refers to collective efforts by government and non-governmental entities to solve problems of security, environment, health, and other issues shared globally by all governments. Global governance is understood to take place at the supranational level, as it transcends the scale of individual nation-states. Formal global governance institutions such as the United Nations would be limited in their impact were they to only work through national governments, hence subnational leaders have increasingly become incorporated into global governance structures.12

The original system of post-Second World War global governance was dominated by nation-states through global institutions, in which city governments had only a passive, indirect role through their respective national governments. Through the last two decades of the 20th century and afterward, greater global connectivity and concentration of political-economic power at the local level coincided with a similar expansion of power at the supranational level.13 As greater global governance efforts through formal institutions took place at the supranational level, so too did efforts among the world’s cities—both in tandem with existing supranational structures and independently in their own new city-based global governance structures.

From this context, Transnational Municipal Networks (TMNs) emerged: TMNs are non-governmental organizations whose membership is comprised of city government leaders from around the world, and which facilitate knowledge and resource-sharing on governance issues among member cities. TMNs can operate independently from formal institutions of global governance, serving specific urban needs, but many also operate in collaboration with formal institutions to advance collective efforts to solve global problems—in both cases, TMNs have allowed distinctly networked bodies of city government leaders to contribute directly to matters of global governance in ways previously not possible.

Several supranational framework agreements and goals provide an ongoing role for cities in global governance: The United Nations’ New Urban Agenda, the Sustainable Development Goal on cities (SDG 11), the Sendai Framework, Addis Ababa Action Agenda, the role of cities in the Paris Agreement, and so forth. In this environment, TMNs are evolving and strengthening both in their capacity to work in tandem with existing formal global governance institutions, and in their operations independently from those structures. TMNs seek to democratically address the concerns of local governments worldwide while also facilitating networking and best practices sharing among them. TMNs focused on broad governance issues include UCLG, Metropolis, and the Global Parliament of Mayors, among others. Similarly, there are TMNs focused on more general aspects of environmental protection. Standing chiefly among them is ICLEI, which works directly in tandem with the UN.

There are also TMNs focusing on specific environmental issues. The Partnerships in Environmental Management for the Seas of East Asia Network of Local Governments (PNLG) is a marine ecosystem protection TMN, and climate change-focused TMNs include C40, Regions of Climate Action (R20), and the Global Compact of Mayors. There are also TMNs whose focus is specific both to region and issue, such as the European Forum on Urban Security and the World Health Organization (WHO) European Healthy Cities network.

TMNs are capable of helping thousands of cities make carbon emission reductions and other governance-related commitments that may otherwise not have occurred, or at least not have occurred as quickly,14 contributing a sui generis impact on global governance. In this way, TMNs constitute new, consequential structures for global governance, fitting within the larger existing global governance structure of formal institutions, nation-states, civil society, non-government organizations, and other actors.15 While city diplomacy of the sort enabled by TMNs impacts global governance, not all city diplomacy has this wide an impact. We might think of the magnitude of the impact of city diplomacy as being relative to the scale(s) at which it operates.

Dyadic city-to-city relationships such as international sister city relationships pair city governments of different countries and facilitate bilateral flows of information, personnel, commerce, and other resources. These relationships are considered city diplomacy because they involve cooperation between city leaders and entities far outside their jurisdictions, and because the greater inter-societal understanding they collectively achieve is understood to decrease the likelihood of conflict between nations.

However, sister city relationships are normally either fully autonomous or subservient to hierarchal jurisdictions of government, do not involve cooperation between cities that are not sister cities, and do not extend beyond the scale of the city level. In this sense, city diplomacy of this sort is scalar. This kind of activity does achieve beneficial social, political, and economic outcomes, but they are highly localized. City diplomacy of the TMN variety, however, involves all participating cities interacting with one another and penetrates through multiple scales beyond the city level, as TMNs organize cities at the regional, national, and international level, and it also incorporates their capacity building efforts with that of larger formal global governance institutions.

TMNs are multiscalar in this way, and can, by way of penetrating multiple scales, be understood as having a grander impact than that of scalar city diplomacy. The total population of cities around the world which may be eligible for membership in TMNs currently exceeds the capacity of the TMNs to manage member cities, but this structural limit may loosen as TMNs evolve and adapt to the growing collective needs of the world’s cities. The city diplomacy of the sort used during the “municipal foreign policy movement” of the 1980s elevated from scalar to multiscalar as networking efforts gave way to new collective bodies of city leaders focused on specific diplomatic causes.

The same dynamic is true today (e.g. the formation of the U.S. Climate Alliance in response to Trump’s withdrawal from the Paris Agreement). It should be understood that city diplomacy does not exist solely as a response to national level stimuli. Broadly, city diplomacy helps advance problem-solving capacity at the local and global level in the areas of commerce, security, health, environment, and other aspects of societal well-being.

However, as political and economic problems of the sort created by Brexit and Trump rise to the level of global governance issues, city diplomacy also offers the means to help fill voids in national



1 Tavares, R. 2016. Paradiplomacy: Cities and States as Global Players. New York, NY: Oxford University Press, 2016.

2 Fry, E. and P. Kresl. 2005. The Urban Response to Internationalization. London: Edward Elgar.

3 Tavares, op. cit.

4 Ljungkvist, K. 2015. The Global City 2.0: From Strategic Site to Global Actor. New York, NY: Routledge.

5 Fry, E. 1989. The New International Cities Era: The Global Activities of North American Municipal Governments. Provo:  David M. Kennedy Center, Brigham Young University.

6 Smith, D.A. and Timberlake, M. , “Cities in global matrices: toward mapping the world-system’s city system”, in P.L. Knox and P.J. Taylor (eds.), World Cities in a World System (New York: Cambridge University Press, 1995), pp. 79-97.

7 Ljungkvist, op. cit.

8 Leffel, B., 2017. “Rebirth of the Municipal Foreign Policy Movement,” CPD Blog, April 5. Available at:

9 Hobbs, H.H. 1994. City Hall Goes Abroad: The Foreign Policy of Local Politics. Thousand Oaks: Sage Publications.

10 Hurley, S. 1988-89. ‘Solidarity, St. Paul Style’, Bulletin of Municipal Foreign Policy, vol. 3, no. 1, Winter, 49.

11 “Gorton Center Discussion Series Presents: Metropolitan Diplomacy – How Cities Are Affecting Foreign Policy Metropolitan Diplomacy: How Cities are Affecting Foreign Policy,” The National Bureau of Asian Research, May 28, 2014. Available at:

12 Amen, M., Toly, N.J., McCarney, P.L. and Segbers, K., eds. 2011. Cities and Global Governance: New Sites for International Relations. Burlington, VT: Ashgate Publishing Company.

13 Swyngedouw, E. 2000. “Elite Power, Global Forces and the Political Economy of ‘Glocal’ Development.” In: G. Clark, M. Feldman and M. Gertler, eds. The Oxford Handbook of Economic Geography. Oxford: Oxford University Press.

14 Acuto, M., Decramer, Morissette, M., H., Doughty, J., and Y. Yap (2017). City Networks: New Frontiers for City Leaders. UCL City Leadership Lab Report. University College London: London

15 Acuto, M. 2013. Global Cities, Governance and Diplomacy: The Urban Link. New York, NY: Routledge.

Benjamin Leffel is a Sociology Ph.D. student at the University of California Irvine, is director of Research for the Tai Initiative, and specializes in global city networking, subnational diplomacy, and U.S.-China relations. His work on subnational diplomacy has informed the work of the British Government Office for Science, the U.S. Department of State, and U.S. local governments. He previously worked on subnational diplomacy issues with the former Special Representative of  Global Intergovernmental Affairs under the Clinton State Department, and he is responsible for the creation of the digital archive on the “municipal foreign policy movement” of the 1980s in the California Digital Library.

Michele Acuto is director of the City Leadership Laboratory at University College London (UCL), where he is professor of Diplomacy & Urban Theory in the Department of Science, Technology, Engineering and Public Policy (UCL STEaPP). Michele is a senior fellow of the Chicago Council on Global Affairs and a fellow of the Programme for the Future of Cities at the University of Oxford. He was previously a fellow at the Institute for Science, Innovation, and Society (InSIS) at the University of Oxford, and a fellow at the Center on Public Diplomacy at the University of Southern California. He has taught at Australian National University, University of Canberra, and National University of Singapore. He holds a Ph.D. from the Australian National University, and is the author of, amongst others, The Urban Link (Routledge), and Global City Challenges (Palgrave).