This paper examines parliamentary diplomacy as a dimension of Portugal’s external engagement, situating the Portuguese Parliament within the broader landscape of European interparliamentary cooperation. While parliamentary diplomacy is increasingly recognised as a complementary practice to executive-led diplomacy, its role in the foreign policy strategies of small EU member states remains insufficiently theorised. The paper addresses this gap by analysing how parliamentary actors contribute to external engagement, political positioning, and normative influence within the European political space.

Empirically, the study focuses on the activities of the Portuguese Parliament in European parliamentary fora, with particular attention to the role of the Representative of the Portuguese Parliament to the European Union and Portugal’s participation in the Conference of Parliamentary Committees for Union Affairs (COSAC). These mechanisms are examined as key institutional sites of interparliamentary dialogue and coordination, enabling parliamentary actors to engage in scrutiny, agenda-setting, and normative exchange within the EU’s system of multilevel governance.

The analysis further considers the participation of Portuguese parliamentary delegations in multilateral parliamentary assemblies, including the exercise of leadership roles and thematic initiatives in areas such as democracy promotion, security dialogue, and regional cooperation. These practices are assessed as instruments of external projection and political visibility, particularly relevant for small states navigating structural constraints within the EU.

Theoretically, the paper brings together scholarship on parliamentary diplomacy with insights from small state studies and soft power theory. It argues that parliamentary diplomacy constitutes a strategic resource through which small states can mitigate structural asymmetries by mobilising deliberative legitimacy, transnational networking, and identity projection. Methodologically, the study is based on qualitative analysis of parliamentary documents, institutional reports, and selected cases of parliamentary engagement at European level.

The proposed paper aims at examining how parliamentary diplomacy builds geopolitical representations of security and terrorism across the Euro-Atlantic and the Eurasian spaces within the Parliamentary Assemblies of the Organization for Security and Co-operation in Europe (OSCE PA) and the North Atlantic Treaty Organization (NATO PA). While the institutional and practice dimensions of Parliamentary Diplomacy have been the object of research, this study aims at complementing the existing literature by introducing a spatial dimension, which remains understudied.

By building on practice-oriented approaches, this study demonstrates that parliamentary diplomacy is not only a flexible and often informal form of diplomacy, which can be alternative and complementary to the traditional governmental diplomacy, but also a practice that produces geopolitical representations.

The paper compares how parliamentary diplomacy is a practice where actors produce and depict representations of security and threat across different institutional settings. The method use is a combination of qualitative discourse analysis with the analytical method of the French School of geopolitics (critical geopolitics). The sources mainly used are parliamentary resolutions, committee reports and debates, which are analyzed through Lacoste’s geopolitical framework, that focuses on actors, representations (values), spaces and territories, rivalries, and scales. It compares how OSCE PA and NATO PA construct a proper representation in which security, in particular terrorism, is spatially located, interpreted and elaborated through a geopolitical lens.

Parliamentary diplomacy builds different geopolitical imaginaries of security and terrorism depending on the actor, the threat, and the geographical scale of the political space in which they operate.

The analysis will focus on three dimensions: 1. The geographical delineation of political membership as a self-representation of the assembly (Inclusive and political for the OSCE PA, exclusive and security-oriented for NATO PA); 2. The representation of threat and response (terrorism as a common challenge which requires more cooperation vs. a terrorism linked to external instability which requires collective defensive action); 3. How geopolitics and representation beyond the respective sphere of membership also define the positioning of the two assemblies.

By integrating a spatial dimension into the practice-oriented approaches to parliamentary diplomacy, the article shows that parliamentary diplomacy is not only a practice related to dialogue and deliberation, but a practice that produces geopolitical orders and shapes how security threats and world imaginaries are defined and represented.

The establishment the EU-UK Parliamentary Partnership Assembly (PPA) under the 2021 Trade and Cooperation Agreement (TCA) marked a significant—yet under-examined—development in the architecture of post-Brexit governance. As the only formal institutional link between the UK and European Parliaments, the PPA is designed to provide a space for interparliamentary dialogue, foster mutual understanding, and potentially enhance democratic oversight of the evolving EU-UK relationship. However, the Assembly’s advisory status, limited meeting schedule, and uncertain political salience raise important questions about its actual contribution to democratic legitimacy.

This paper critically examines the PPA as a case study in parliamentary diplomacy and evaluates its capacity to reinforce democratic accountability within an executive-heavy post-Brexit governance framework. Drawing on theories of interparliamentary cooperation, input/output legitimacy, and treaty scrutiny, the paper analyses three interrelated aspects: (1) the institutional design and democratic potential of the PPA; (2) the role of UK and European parliamentary actors in shaping transnational accountability and mutual cooperation in bilateral and multilateral policy making (eg, security, climate change, AI governance); and (3) the broader implications for ensuring scrutiny of international agreements.

Methodologically, the paper combines documentary analysis of PPA rules and meetings with insights from post-Brexit scrutiny activities of relevant UK and EU parliamentary committees, while drawing lessons from the differing contexts and approaches that inform the UK and European parliaments’ international engagement. It also considers proposals for PPA reform, such as enhancing Northern Ireland representation or creating dedicated sub-structures for regional or sectoral engagement.

Finally, the paper argues that the PPA is a valuable but fragile innovation whose effectiveness will depend less on its formal design and more on the political will of legislators to engage meaningfully. The study contributes to broader debates on the evolving role of parliaments in global politics and the democratic governance of international treaties.