Majority Leadership in the U.S. Senate: Balancing Constraints By ...

parties have as their proximate goal the passage of policy which can help with individual reelection efforts. Thus, the Senate majority leader's party demands policy outcomes that will help fulfill the electoral goals of members (Rohde, 1991). However, party caucuses are rarely monolithic in preferences or behaviors, and partisan demands on Senate majority leaders are rarely uniform. Instead, partisan constraints fluctuate with the size of the Senate majority leader's majority. A narrow majority places the Senate majority leader in the position of negotiating with the minority to accomplish the policy goals of the party. However, that narrow majority also places a burden on the caucus to remain unified for a narrow win. This incentive is the principle of the “minimum winning coalition” (Riker, 1962). As the margin of majority increases, greater numbers by definition mean greater interests. With more heterogeneity, the partisan coalition tends to fracture as the risk of losing a vote lessens and thus defection carries fewer consequences. But the prospect of defections leads to other defections—why should one faction be excused on principle from the coalition while another must remain because the party cannot afford to lose any more votes? Plus, party factions tend to activate others in an action-reaction response. Thus, the Senate majority leader is constrained by his own partisans.

Senate

The Senate majority leader is more than a senator and more than a partisan. As functional head of the upper chamber of the legislative branch, the majority leader must act to preserve institutional prestige that is the currency of legitimacy. In an era in which public opinion of Congress is exceedingly low (Hibbing & Theiss-Morse, 1995), the Senate majority leader must preserve the legitimacy of the body. From Washington's explanation to Jefferson's ideas about the tempering nature of the upper chamber, the Senate is perceived by members and observers alike to be the more deliberative body, the stalwart against the passions of the House. However, many perceptions of the Senate as a collegial, orderly club have been transformed in recent decades (Byrd, 2005; Sinclair, 1989), while the idea of the Senate as wiser, fairer, and less partisan than the House remains.