<![CDATA[Vietnam–Thailand’s elevation to a Comprehensive Strategic Partnership in May 2025 marks a critical juncture in mainland Southeast Asian diplomacy. Although this relationship is formally bilateral, the two countries describe their cooperation as connecting supply chains, local economies, and sustainable development strategies through “Mekong-centered sub-regional cooperation mechanisms.” Moving beyond traditional international relations approaches that treat the Mekong merely as a functional or material arena, this article approaches subregional diplomacy as a fundamentally communicative project. Written from the vantage point of Vietnamese scholarship, the study applies critical discourse analysis, framing analysis, and the strategic narratives approach to 14 official Thai, Vietnamese, and Lao texts, issued mainly in 2025–2026, with Laos’s 2021 development plan as a contextual text. The analysis demonstrates how state actors discursively construct the Mekong as an “intermediary space” to reorganize spatial influence and manage interdependence. Furthermore, it reveals how diplomatic language positions Laos not as a passive geographic buffer but as a “hinge state”: Thai texts tie Thailand’s own plans to Laos’s land-linked strategy, a Vietnam–Laos joint statement frames Lao access to the sea as a shared objective, and Laos’s development plan and Lao state news reports present Laos in that connective role. As such, the article shows that the communicative dimension runs deeply through material mechanisms of mediation, such as logistics, water resources, and non-traditional security, illustrating that modern diplomacy relies as much on the strategic production of meaning as on material capabilities.]]>
