Extension of the Portfolio Allocation Model to Surplus Majority Governments: a Theoretically Salient Case Study

Scholars have long studied the conditions under which the cabinet making process will result in minority, surplus majority, or minimum-winning governing coalitions in parliamentary systems. A recent contribution, Laver and Shepsle's portfolio allocation model, argues that surplus majority coalitions can only form when the number of salient policy dimensions in the political system is greater than two. We argue that majority surplus coalitions can result when there are only two salient policy dimensions and a merely strong party, not able to win a standoff, can obtain a government occupying a policy position closest to its ideal point by dividing policy jurisdictions across two or more cabinet positions. The 1996 surplus majority in the Lithuanian Seimas illustrates our argument. The Challenge In political systems in which government formation and survival depends upon the legislature, governing coalitions of political parties are necessary when no political party commands an absolute majority. The process of cabinet making in such systems may result in a parliamentary coalition constituting the smallest absolute majority possible given the size of existing factions (a minimum-winning coalition), one constituting more than that necessary for a minimum winning coalition (a surplus majority coalition), or less than a