The anti-entrenchment critique of Senate rules rests on two pillars. The first, which I will consider here, is an analogy to a line of cases holding that a later statute trumps an earlier one, even if the earlier statute purported to be entrenched against repeal. Thus, for example, a statute which establishes a particular location as a “permanent capital” would not prevent the legislature from later moving the capital. See Ohio Life Ins. & Trust Co. v. Debolt, 57 U.S. 416 (1853). As the Supreme Court explained (in language quoted by the December 12 letter): “[N]o one legislature can, by its own act, disarm their successors of any of the powers or rights of sovereignty confided by the people to the legislative body.” Id. at 421. The argument is that a legislative rule which prevents a simple majority from acting similarly disarms the legislative body of “the powers or rights of sovereignty.”
At the outset it should be noted that the line of cases in question is entirely related to statutes; there is no case suggesting, even in dicta, this principle applies to legislative rules. To the extent that the courts have spoken about entrenchment of legislative rules, it is to affirm that the matter is one for legislative, not judicial, cognizance. Thus, in dismissing the Common Cause lawsuit (which challenged both the filibuster and its entrenchment), Judge Sullivan noted the absence of “any [constitutional] language that expressly limits the Senate’s power to determine its rules, including when and how debate is brought to a close. . . . Plaintiffs have not demonstrated that the Presentment Clause, the Quorum Clause, or any other constitutional provision explicitly requires that a simple majority is all that is required to close debate and enact legislation.”