Conversation #85

The encyclopedia Britannica defines diplomacy as “the established method of influencing the decisions and behaviour of foreign governments and peoples through dialogue, negotiation, and other measures short of war or violence.” We note two things about this definition. First, it is expansive in that it may encompass a broad range of actors, actions and strategies. Second, it precludes violence and acts of war. Effective diplomacy hinges on participants’ capacity for identifying and leveraging areas of common interest to realise mutual gain. Furthermore, it is the sine qua non for world peace. Therefore, our aim here is to consider how city diplomacy can and is contributing to the project of world peace. But first, we explore why city diplomacy is needed at all.

Even though nation-to-nation diplomacy remains the “default setting” in geopolitics, it is increasingly questioned in light of recent failures to prevent global crises through diplomacy. From ongoing and extensive armed conflicts that threaten to escalate and extend to other regions, to the persistent failure to jointly address global challenges like climate change, countries struggle repeatedly to align diverse national interests and reach workable agreements. We also witness diplomatic shortcomings beyond the national level. The European Union and the United Nations continue to falter when facing challenges like migration, health, the environment, and armed conflict. Rising nationalism and political polarisation further handicap national decision-makers by making them politically vulnerable to the manoeuvring of a handful of oppositional forces. This greatly hinders governments’ capacity to respond in unison to transboundary challenges that require international remedies.

Weak international diplomacy makes a hard landing in cities. The immediate effects of wars and international crises are often left to be managed by cities. From refugee crises to climate change, the past two decades provide numerous examples of how cities mobilise in response to diplomatic failures, with many of them deciding to act collectively to develop common solutions. A meaningful point of departure for interrogating the efficacy of these efforts is to briefly examine current trends and innovations in city diplomacy.

We observe three notable trends in city diplomacy. The first is that city diplomacy is multi-modal and therefore has many avenues for non-violent exchange. More specifically, local governments adopt several configurations when engaging in international relations. Three modalities, in particular, have attracted scholarly attention: City-to-City partnerships (C2C), transmunicipal networks (TMNs), and cross-border cooperation (CBC).

CBCs refer to cooperative efforts between communities in border regions to address shared challenges and jointly leverage socio-economic opportunities. While many of these projects aim to stimulate economic development in border regions, they also encourage friendly relations between neighbouring countries which may be helpful during periods of crisis – as was witnessed during the COVID-19 pandemic. TMNs also demonstrate the power of urban diplomacy. Actions taken by city networks like the Global Parliament of Mayors and Eurocities demonstrate that, when they work together, cities can bypass national governments to implement localised solutions while contributing to global goals. Finally, there are C2C partnerships, which typically involve formal agreements between two cities. Cities may choose to adopt hybrid configurations (Kurniawan et al., 2013) and may engage in city diplomacy not just to solve common problems but also to gain political influence and accrue soft power (Curtis & Acuto, 2018).

The second trend is that cities are increasingly engaging in areas previously reserved for action and diplomacy by the nation state. While much has been written about the different climate change-driven city partnerships and networks, we are increasingly witnessing cities collectively encroach into areas once relegated to state-level decision-making and action, like migration management and nuclear disarmament (Jakobi, 2025). We suspect that this trend towards greater collective action by cities is driven in part by policy learning that occurs when cities encounter one another through multiple memberships in networks (Nguyen Long & Krause, 2021). The frequency of these interactions increases cities’ familiarity with one another and can build momentum towards future joint action.

Finally, the third trend we observe is that city diplomacy – like national diplomacy – can sometimes be futile and constrained. National governments may impose restrictions on local governments’ diplomatic activities (Curtis & Acuto, 2018; Oomen & Baumgärtel, 2018), especially in areas where foreign relations are sensitive. For instance, cities may face backlash for maintaining partnerships with countries experiencing diplomatic isolation, as seen in the case of some U.S. cities engaging with Cuban municipalities. Furthermore, national politics can undermine local initiatives. Economic sanctions or shifts in foreign policy can disrupt established city-to-city partnerships and limit their potential. Finally, power imbalances between cities can lead to problematic dynamics and to the adoption of ill-fitting, cookie-cutter, and counterproductive policies (Mayer & Nguyen Long, 2021).

A last reflection: 68 percent is the figure commonly associated with the future of cities. It is the estimated share of the global population that will be concentrated in urban areas by 2050, and indeed, the global urban population has outnumbered the rural population for around a decade. In short: the majority of the world is urban. This requires increased political representation in both national and global arenas by cities. It speaks to the imperative for more engaged scholarship on cross-national lesson-drawing by cities (Hambleton, 2014). To understand what that may mean for the future, in terms of the political positions and strategies that cities tend to adopt, one need not look further than urban diplomacy for clues.

Selected references:

Curtis, S., & Acuto, M. (2018). The Foreign Policy of Cities. The RUSI Journal, 163(6), 8–17. Hambleton, R. (2014). Leading the Inclusive City: Place-Based Innovation for a Bounded Planet. Bristol University Press. Jakobi, A. P. (2025). Engaging in and with complexity: Local actors, Mayors for Peace and the global nuclear order. Cambridge Review of International Affairs, 38(3), 319–341. Kurniawan, T. A., Puppim de Oliveira, J., Premakumara, D. G. J., & Nagaishi, M. (2013). City-to-city level cooperation for generating urban co-benefits: The case of technological cooperation in the waste sector between Surabaya (Indonesia) and Kitakyushu (Japan). Journal of Cleaner Production, 58, 43–50. Mayer, L., & Nguyen Long, L. A. (2021). Can city-to-city cooperation facilitate sustainable development governance in the Global South? Lessons gleaned from seven North-South partnerships in Latin America. International Journal of Urban Sustainable Development, 13(2), 174–186. Nguyen Long, L. A., & Krause, R. M. (2021). Managing policy-making in the local climate governance landscape: The role of network administrative organizations and member cities. Public Administration, 99(1), 23–39. Oomen, B., & Baumgärtel, M. (2018). Frontier Cities: The Rise of Local Authorities as an Opportunity for International Human Rights Law. European Journal of International Law, 29(2), 607–630.