I am starting work on a piece—a contribution to an edited collection—that will examine the contemporary relevance of the doctrine of parliamentary sovereignty. The following represents a preliminary sketch of the arguments that the chapter will advance—an abstract of sorts. Any comments (via the comment function below or by email) would be welcome.
For all that it is fashionable to criticise it, the Diceyan notion of parliamentary sovereignty remains a remarkably resilient feature of the United Kingdom’s constitutional arrangements. It seems to be capable of withstanding constitutional changes and innovations that, at least at some level, might be thought to challenge it. Examples of such developments include British membership of the European Union (and the associated doctrine of the supremacy of EU law); the restraining effect (at least upon the UK as a matter of international law) of international obligations (of which the UK’s treaty obligations under the European Convention on Human Rights are a familiar example); the devolution of authority to new legislatures; and the growing prominence of common-law “constitutional rights”, including tentative judicial suggestions as to their constitutional fundamentality.
One way of looking at developments such these is to place them in opposition to a pristine notion of parliamentary sovereignty, according to which Parliament’s legislative freedom is unbounded. The narrative implicit in that classical doctrine seems far-fetched when the constraining influence such developments is factored into the analysis. Can Parliament really legislate in opposition to its obligations under the ECHR? Could it reverse—or even abolish—devolution, or (more modestly) override the wishes of a devolved legislature in a particular field? Without leaving the EU, is it realistic to propose that a “sovereign” Parliament is free to derogate from EU law, provided that it expresses its intention to do so in sufficiently clear terms?
The answers to those questions may well be “no”: but the nature of the questions are arguably such that the notion of parliamentary sovereignty is not itself implicated. In other words, Parliament’s “inability” to do these things may explicable in a way that leaves the notion of parliamentary sovereignty untouched. (This is not to suggest, however, that I am seeking to defend the sovereignty doctrine in the sense of attempting to establish its adequacy: rather, I argue that for all that it might be accurate viewed in its own terms, it is an incomplete—and in that sense inadequate—way in which to understand the British constitution and Parliament’s place within it.) How, then, might the phenomena sketched above be characterized, if not as “challenges” to parliamentary sovereignty?
They can—and, arguably, should—be understood in terms that present no outright challenge to the orthodox account of parliamentary sovereignty. Rather, they constitute, give rise to or presuppose a network of constitutional norms—legal and non-legal, written and unwritten—that, while not technically inconsistent with parliamentary sovereignty, supply crucial features of the context within which Parliament’s legislative authority is to be understood and the legitimacy of its exercise assessed. Although they do not rule out—in the sense of making unconstitutional as a matter of domestic law—any particular legislative action by Parliament, they condition the exercise of its power and inform assessments of what might be termed its “soft constitutionality”. (I will, however, go on to question whether the distinction implicit in this characterization—between hard and soft forms of constitutionality—is helpful.)
The doctrine of parliamentary sovereignty, if accepted, necessarily precludes the existence of hard-constitutional limits on Parliament’s legislative authority: the absence of such limits forms the essence of the sovereignty doctrine. In contrast, there is no logical difficulty in conceiving of constitutional factors—including the rule of law, common-law constitutional rights, the UK’s international legal obligations (including under the ECHR and the EU Treaties), and the principles of multilayered constitutionalism implicit in the devolution settlements—as benchmarks against which the soft constitutionality of UK legislation may fall to be assessed. Unilateral interference in a devolution settlement or flagrant disregard of the UK’s international human-rights obligations may therefore be regarded as unconstitutional in a soft sense even though the doctrine of parliamentary sovereignty secures the hard constitutionality of such legislation. This echoes familiar distinctions between (for example) practices that may be unconstitutional, in the sense of breaching established constitutional conventions, yet nevertheless legal.
We might, however, question the usefulness or appropriateness of the distinction between soft and hard forms of constitutionality. Arguably, it presupposes a particular perspective that overlooks an increasingly prominent feature of the UK’s constitution. More precisely, it adopts a domestic-legal lens and treats considerations of that nature paradigmatically. This may be thought insensitive to what might be termed the multidimensional nature of the UK’s constitution, which, in turn, makes it inappropriate to seek to understand that constitution only through the one-dimensional prism of parliamentary sovereignty. The notion of multidimensionality consists not only in the multilayered nature of the modern constitution—which encompasses or intersects with several tiers of authority at the domestic and international levels—but also its sometimes-Janus-like politico-legal nature.
Its multidimensional nature renders inadequate any attempt to explain or understand the constitution from a single perspective, such as that which is at least implicit in the doctrine of parliamentary sovereignty. That doctrine exists on axes that are legal and domestic in nature, and, as such, may not come into directcontact—or explicit conflict—with other constitutional axes that may be political or non-domestic in character. This accounts, for instance, for the possibility of legislation being valid and lawful in domestic-legal terms but contrary to the UK’s obligations under the ECHR or the EU Treaties. However, this does not mean that the restraining force of those other constitutional axes can be wholly discounted. They may not constitute constraints viewed from the perspective of the particular part of the constitution that parliamentary sovereignty inhabits—but the particular constitutional space occupied by parliamentary sovereignty, as a domestic-legal doctrine, is accounted for by only a subset of the axes that form the constitution’s several dimensions. The fact that non-legal and legal-non-domestic factors do not directly collide with the domestic-legal doctrine of parliamentary sovereignty does not rob such factors of constitutional relevance, once the constitution is conceived of in multidimensional terms. Nor does it necessarily mean that non-legal and legal-non-domestic factors can properly be relegated to a second-order status by means of treating them only as benchmarks of a soft form of constitutionality.
This analysis helps to explain why (as Dawn Oliver has noted) there is a degree of uncertainty about what would happen if there were a constitutional crisis—e.g. if Parliament enacted legislation that was flatly inconsistent with a fundamental constitutional principle, or if the courts refused to acknowledge a provision in an Act of Parliament as a valid law (perhaps because, in the first place, it infringed a fundamental constitutional principle). Such extraordinary circumstances have the effect of bringing different dimensions of the constitution face to face with one another in a way that appears to call for their hierarchical ordering, so as to determine whether one may assert priority over the other. That ordering function is one that may be served by a written, higher-law constitution: indeed, precisely that function is served by such constitutions in many countries. One of the defining features of the UK’s constitution, in contrast, is that its different dimensions sit in an ambiguous relationship with one another in the absence of the potentially unifying, or at least mediating, force of an authoritative constitutional text.
Here, however, we encounter perhaps the greatest paradox of the UK’s constitution. The fact that the constitution encompasses many dimensions, only one of which is occupied by parliamentary sovereignty, helps to guard against the eventuation of precisely those circumstances that might call for a clearer constitutional ordering. This is because the constitution’s different dimensions sit not in absolute isolation from one another, but in relationship and tension. It is therefore often possible—and in the interests of relevant institutional actors—to avoid constitutional crunch questions that, if directly confronted, would call for the interrelation of the constitution’s many dimensions to be articulated and ordered in a more explicit way. It is in the multidimensional character of the constitution, and the fact that those different dimensions occupy constitutional universes that are not merely parallel to one another but which intersect in subtle-yet-important ways, that the fundamental nature of the UK’s unwritten constitution—and the complexity of Parliament’s place within it—consists.
Where does this leave us? Is Parliament sovereign? Yes, it is: or, more precisely, the doctrine of parliamentary sovereignty is an accurate statement of domestic constitutional law. But the significance of that fact diminishes once we recognise that it represents only one fragment of a much larger constitutional tableau.