The 2003 Intergovernmental Conference in the EU was halted from December 2003 till March 2004. The reason was the opposition against the proposed new double majority system of Qualified Majority Voting in the Council of Ministers. The main opponents were Spain and Poland. They later agreed to a new Treaty with a modified double majority QMV system. This thesis examines possible explanations for why Spain and Poland agreed in the end, based on Arild Underdal's Law of the Least Ambitious Program. Very little evidence is found to suggest that Spain and Poland received enough concessions or sidepayments from the other member states to make it rational for them to change their positions, and we still find that the end-result constituted a substantial change from the status quo ante. Other explanations are tentatively examined to suggest further research approaches.