Third level of relations with superpowers: A comparative analysis of EU subnational cooperation with the USA and China

European cities and regions are increasingly influential in the heterarchical structures of world politics, engaging in multi-level partnerships and shaping national foreign policies. This dynamic extends beyond Europe, encompassing interactions with global powers. This paper presents a comparative analysis of European subnational cooperation with the United States and China, exploring these relationships' nuances, similarities, and driving factors. The analysis is grounded in comprehensive surveys conducted across cities and regions within the European Union in 2020/21, 2022/23 and 2023/24. These surveys were complemented by interviews with city and regional officials, providing a rich dataset for examining EU subnational links with US-American and Chinese sub-state partners. The focus extends to smaller cities, often overlooked in diplomatic studies, thus offering a more inclusive and comprehensive view of urban diplomacy. Our research maps and analyses the various forms of subnational engagement between EU urban entities and the governments of the USA and China. We develop a matrix of conditions that either facilitate or hinder this cooperation. Critical factors considered include city size, geographic location, historical ties, presence of diaspora communities, the strength of business links, academic centres, institutional frameworks, and the attitudes of local leadership. Furthermore, the paper evaluates the impact of these subnational ties on the broader EU foreign policy stance towards the USA and China. Doing so significantly contributes to understanding the EU's foreign policy, EU international relations, and the multi-level nature of these interactions. This research is pivotal for scholars in international relations and urban diplomacy as well as the EU's global actorness, offering new insights into how subnational entities navigate complex global relationships and contribute to shaping international policies, particularly in the context of relations with the two superpowers.