The original Congress could pass an additional entrenching provision, R', which provides that R can be repealed only with a two-thirds majority, but then of course the next Congress could repeal R' with a simple majority, and so on down the line.
The possibility of circumvention does not supply an objection to entrenching statutes in particular; if that possibility proved the conceptual impossibility of entrenchment, it would also prove the conceptual impossibility of binding future decisionmakers by means of ordinary constitutional and statutory provisions.
We have encountered the view that entrenching statutes cannot possibly have any policy value, and therefore they either should be unconstitutional for that reason or should not be a topic of academic debate, for no reasonable legislature would want to enact them.
We assume throughout that all entrenching statutes otherwise fall within the scope of Congress's affirmative authority to enact legislation under the enumerated powers set forth in Article I, Section 8, in the Necessary and Proper Clause, and in a miscellany of other constitutional provisions.
The initial puzzle of the Vesting Clause argument is that, on its face, the grant of "legislative Powers" to Congress simply does not speak to the question posed by entrenching statutes.
Sunset clauses are the mirror image of entrenching clauses and might also be said to control the authority of later legislatures: An entrenching clause forbids the later legislature to prevent a statute from remaining in force by an affirmative repeal, while the sunset clause forbids the later legislature to allow a statute to remain in force by declining to repeal.
35) On the other side of the originalist ledger, Madison himself recognized the validity of entrenching statutes by classifying political acts into three categories: (1) constitutions; (2) laws irrevocable at the will of the legislature; and (3) ordinary laws that are not irrevocable.
Even were some constitutional historian to discover unequivocal evidence that the Framers assumed entrenching statutes to be invalid, that evidence would demonstrate no more than a background assumption at the level of specific intentions, an assumption untethered to any particular constitutional text.
40) He thereby wanted to conclude that entrenching legislation cannot bind subsequent Parliaments, but we might more plausibly see these as examples of highly successful entrenchments, given that they had a lifespan longer than those of many constitutions.
Entrenching statutes, then, are constitutional amendments enacted outside the exclusive constitutional process for enacting amendments.
Entrenching provisions are not amendments, nor are they "equivalent" to amendments in either a de jure or a de facto sense.
Indeed, the argument from Article V gets the structural argument against entrenching statutes precisely backwards.