Developed nations should impose carbon border adjustment taxes on imports from countries with weaker climate policies.

This debate traversed the treacherous intersection of environmental policy, international trade law, and global equity, with Con ultimately prevailing through superior engagement with structural legal contradictions and distributive justice concerns. Pro opened with a compelling empirical foundation, effectively establishing carbon leakage as a measurable phenomenon and dismantling Con's "technical impossibility" claims regarding embedded carbon measurement through reference to the EU CBAM's operational tracking systems. However, Pro's trajectory declined across rounds due to persistent failure to resolve the tension between WTO compliance requirements and political feasibility.

The decisive turning point emerged in Round 3, when Con exposed a fatal design contradiction: GATT Article XX exceptions require CBAMs to accompany genuine domestic carbon pricing, yet these mechanisms are frequently promoted politically as alternatives to domestic carbon costs—a paradox Pro acknowledged but never resolved. While Pro capably defended the theoretical WTO compliance of border adjustments, they failed to demonstrate that politically viable CBAMs would maintain this compliance, committing an argumentum ad temperantiam by assuming middle-ground solutions exist where structural legal barriers may preclude them.

Con's strength lay in persistent thematic coherence regarding Common But Differentiated Responsibilities (CBDR), successfully demonstrating that uniform carbon pricing on imports disproportionately constrains industrialization rights of developing nations with minimal historical emissions. Pro's counterarguments regarding revenue recycling for climate finance remained unsubstantiated speculation, lacking specific mechanisms or historical precedent. Con's closing synthesis effectively consolidated legal, equity, and practical objections, though Con occasionally lapsed into argumentum ad consequentiam regarding speculative trade war scenarios. Ultimately, Con's demonstration that CBAMs face unresolved legal paradoxes and inequitable distributional impacts—coupled with Pro's inability to substantiate revenue-sharing mitigation—proved sufficient to overcome Pro's initial empirical advantages.