We study quid pro quo trade negotiations—i.e., agreements in which each country simultaneously concedes on one issue in
exchange for a reciprocal concession on another—within the canonical Nash bargaining framework. Departing from the standard
“single-issue” paradigm, we model negotiations as a multi-dimensional bargaining problem in which the set of feasible utilities is
non-convex due to issue linkages and political-economy constraints. We derive the Nash solution and show that quid pro quo
exchanges increase the bargaining surplus relative to issue-by-issue negotiations if and only if concessions are negatively correlated
in political cost across countries. Calibrating the model to data on 1995–2022 WTO bargaining episodes, we find that quid pro quo
deals raise expected joint surplus by 8–14 % relative to single-issue talks, with the largest gains realized in agriculture–services
linkages. Counterfactual analysis indicates that a 10 % fall in bargaining frictions would have accelerated the conclusion of the Doha
Round by roughly three years. Our results formalize a rationale for issue linkage that is distinct from standard terms-of-trade
manipulation and provide new guidance for structuring efficient multilateral negotiations.