Twenty-five years after its founding, the Shanghai Cooperation Organisation holds its anniversary summit in Bishkek from 31 August to 1 September 2026, against the backdrop of the war between the United States and Iran, renewed exchanges of fire in the Strait of Hormuz, and mounting American economic pressure on Tehran’s partners. This analysis argues that the SCO does not function as an alliance in the process of consolidation, but as a two-tier structure: it multilateralises diplomatic access, legitimacy and consultation, while leaving the costly decisions — defence, intelligence, energy, exposure to sanctions — to bilateral relationships. Iran holds full membership without any collective security guarantee; the Russian–Iranian treaty of January 2025 contains no mutual defence clause, while the intelligence support described by American officials travels through a bilateral channel. Russia and China meet within the SCO yet negotiate gas separately, competing meanwhile for influence in Central Asia. India, Türkiye and Pakistan confirm that the organisation imposes no strategic alignment. The summit’s real outcome will be visible in the bilateral meetings, not in the group photograph.