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There has been an extensive debate over the role and strength of political parties in the American Congress. While this has illuminated many interesting aspects of legislative politics, the debates remain far from settled. We seek to contribute to the debate by focusing on two important but neglected aspects of legislative politics: the separation of powers and majority rule instability. Previous research on parties in Congress has either assumed that the policy space is one dimensional or that legislative institutions such as the committee system create a structure-induced equilibrium (Shepsle 1979); in other words, scholars have assumed away the problem of instability in social choice under simple majority rule. However, Aldrich (1995) argues that it is precisely the lack of an equilibrium that leads members to form a coalition (i.e. political party). The uncertainty of the outcome surrounding majority rule leads risk-averse members to form a coalition to avoid being in a situation that makes them worse off. Further, following the insights of Sinclair (1992), we note that incentive to organize is greater when there is an ideologically opposed executive. This paper discusses a set of proposed experiments that investigates whether legislative parties/coalitions emerge when an equilibrium in preferences under simple majority rule does not exist. Specifically, we propose to investigate whether members will form a coalition by one member delegating agenda control to another member when there is instability in social choice. Further, we propose to investigate whether this delegation is more likely when the external veto player has preferences that are divergent from the majority party’s preferences.