In Discussion paper No. 1288 Research Affiliate Mika Widgrén assesses national and supranational influence in relation to changes in inter-body relationships in the European Union, concentrating mainly on the Council-Commission relationship.

Firstly, the paper looks at the relationship between the Council and the Commission by applying the probabilistic interpretation of the standard measures of voting power of cooperative games, namely the Shapley-Shubik index and the Banzhaf index. Secondly, it analyses the impact of alternative rules and compares the problems they have with the current rule. Finally, the paper investigates how the problems related to the Commission's increased independence might be avoided. The author argues that in the current system the Commission is not independent of the member states. This property could potentially have negative effects on Union-wide policies via linked decisions or the so-called restaurant bill problem. In terms of voting power, the decisive power of the Commission need not be increased.