The primary goal of this research was to chart and explain the evolution of the European Parliament and the supranational party system. This was accomplished through the modification and then application of the macro and micro models of institutional development founded in the American congressional literature to the evolution of the EP's organizational structures, the supranational party group system, and the party groups. The macro model was used primarily to predict the timing of institutional change, while the micro model suggested the character of reform based on an understanding of the goals of the actors, the rules of the game, and who had the power to effectively pursue change.

As predicted by the macro model, the timing of the internal institutional development of the EP, as well as the transformation of the party group system, was connected to large exogenous increases to its political power and authority. The micro model was similarly successful in predicting the character of internal institutional reforms and the type of party group system based on an assumption of strategic action by the EPP and PES as they pursued their policy goals. Both models fell short of a satisfying explanation of internal party group reform; however, the reason for their lack of success lies more with the stunted nature of this evolution than with any inherent weakness in the models.

In this final chapter I briefly summarize the findings of the previous chapters and discuss some additional questions that arise naturally out of this research, in particular, to what extent are the macro and micro models of institutional development generally applicable beyond the American congressional context?