Rather than portray institutions as de jure constraints on behavior that bind in all circumstances, recent formal theories of legislatures have begun to portray institutions more plausibly as de facto constraints on behavior in most circumstances. This subtle difference is usually regarded as insignificant because of the willingness and ability of leaders or their agents to enforce normal ways of conducting legislative business. A convincing empirical investigation of this view of institutions backed by leaders requires a joint test against an alternative theory. This paper examines a legislative history that proves to be a useful test case and uncovers evidence missed by two previous studies. To the extent that leaders played a discernible role, the key body was the Rules Committee, which facilitated rather than thwarted the attack on the so-called normal way of doing business. Almost without exception, our findings are consistent with a simple, no-institutions, no-leadership, median-voter theory.