 According to most theorists, another important feature of constitutionalism is that the norms imposing limits upon government power must be in some way, and to some degree, be entrenched, either legally or by way of constitutional  convention.[7]  In other words, those whose powers are constitutionally limited—i.e., the institutions of government—must not be constitutionally at liberty to change or expunge those limits at their pleasure. Most written constitutions contain amending formulae which can be triggered by, and require the participation of, the government bodies whose powers they limit. But these formulae invariably require something more than a simple decision on the part of the present government, through e.g., Presidential fiat or simple majority vote in the legislature, to invoke a change. Sometimes constitutional assemblies are required, or super-majority votes, referendums, or the agreement of not only the central government in a federal system but also some number or percentage of the governments or regional units within the federal  system.[8]  Entrenchment not only facilitates a degree of stability and predictability over time (a characteristic aspiration of constitutional regimes), it is arguably a requirement of the very possibility of constitutionally limited government. Were a government institution entitled, at its pleasure, to change the very terms of its constitutional limitations, we might begin to question whether there would, in reality, be any such limitations. Consider Regina once again. Were she entitled, at her discretion, to remove (and perhaps later reinstate) the constitutional restriction preventing her from legislating on some religious matter on which she had strong views, then it is perhaps questionable whether Regina could sensibly be said to be bound by this  requirement.[9]  On the other hand, were there a constitutional rule or convention specifying that Regina is entitled to remove this restriction only if she succeeds in convincing two thirds of her subjects to vote for the change, then one might feel more comfortable speaking of constitutional limitation. Of course this constitutional meta-rule or convention is itself subject to change or elimination—a fact that raises a host of further puzzles. For example, does such an act require application of the very rule in question—i.e., two third’s majority vote—or are the sovereign people of Regina’s society at liberty to change or expunge it at their pleasure? If we accept (a) the distinction between government and sovereignty urged above; (b) that ultimate sovereignty resides in the people whom Regina governs; and (c) that sovereignty cannot be self-limiting, (X cannot limit X) then we might sensibly be led to conclude that the constitutional meta-rule—and hence the constitutional regime of which it is an integral part—both exist at the pleasure of the general population of Regina’s society. Entrenchment may be an essential element of constitutional regimes, but it would seem that constitutions neither can nor should be entrenched against the actions of a sovereign people.