While it is acknowledged that the multilateral system is not functioning adequately in the present polycrisis, the question of how to transition to something better tends to oscillate between two extremes: on the one hand, small operational changes to the existing Bretton Woods-era machinery; on the other hand, new but still untested ideas -such as leadership by middle powers and alternative coalitions- that promise a fundamentally different kind of governance. The following two sessions will examine the transition pathways between these poles: what can be reformed now within the visible “peak” of today’s system “the operational parts of the present multilateral system”, and what must be built in the submerged “foundation” legitimacy, decision rights, shock absorption, among others, and how we can sequence reforms so the new sustainable architecture, aimed at global efficiency and fairness, becomes real rather than aspirational.