Brexit, sovereignty, and the contemporary British constitution: Four perspectives on Miller

To say that the Miller case has stimulated a wide-ranging constitutional debate would be to engage in rash understatement. The pages of the UK Constitutional Law Association Blog, in particular, are replete with posts that examine the issues raised by the case from a rich variety of perspectives and which advance a broad spectrum of views. As the debate has progressed, I have increasingly found myself wondering why the questions raised by the case have invited such strongly contrasting answers from those who have contributed to the discussion.

Indeed, a particularly striking feature of the debate is the way in which scholars have adopted sharply opposing positions on questions that are quite fundamental in nature. Matters that are considered by some to be so obvious as to amount to ‘Constitutional Law 101’ are regarded by others as not only contestable but wrong. Debate, of course, lies at the core of the academic endeavour, and the fact that Miller has prompted such discussion is doubtless a silver lining to what, for some, is an otherwise singularly dark, Brexit-shaped cloud. But the question remains: why should the case stimulate should sharp disagreement? Some answers to that question have already been offered in a valuable piece written by my colleague Paul Daly, in which he addresses the ‘legal and political faultlines’ that have characterised the debate so far. In this post, I focus specifically on the principle of parliamentary sovereignty and its relevance to the issues raised, and disagreements stimulated, by Miller.

That principle, it seems to me, forms a key intersection point that both connects and distinguishes many of the questions in Miller. For all that it is axiomatic, the sovereignty principle is emblematic of many of the uncertainties that exist in relation to the contemporary British constitution. That sovereignty is in play in this context is inevitable, given that questions about the extent of the executive’s prerogative power necessarily fall to be resolved in the light of a sovereignty principle that was itself beaten out, centuries ago, on the anvil of Crown’s waning unilateral authority. But this inevitable dimension of the case is joined by others, thanks to the potentially constraining effect of the UK’s new territorial constitution, still-unanswered questions about EU law’s implications for parliamentary sovereignty, and issues concerning the interaction of that doctrine with the notion of popular sovereignty as manifested in the Brexit referendum.

The purpose of this post is not to argue that a particular view ought to be taken of parliamentary sovereignty, and that Miller ought therefore to be decided in a particular way. Rather, my point is that the principle of parliamentary sovereignty, for all that it is pertinent to the questions raised by Miller, is unlikely to be dispositive of those questions. The reason, I suggest, is that within the factual matrix of the case, the extent of the pull (one way or the other) exerted by the sovereignty doctrine is contestable. It follows that, for all that the sovereignty principle might appear to be the key to resolving the issues that arise in Miller, reality is perhaps the other way around — meaning that it is through the resolution of the questions raised by Miller that the shape of the modern doctrine of parliamentary sovereignty might emerge more clearly.

In this piece, a work-in-progress that forms an initial sketch of a longer piece that I am writing, I briefly explore four areas in which the sovereignty principle interacts with the issues at stake in Miller, each of which is illustrative of distinct — sometimes overlapping, and sometimes contrasting — facets of the principle. Taken in combination, these four sites of interaction form a tableau upon which many of the uncertainties pertaining to the modern constitution are etched. The four relevant relationships, then, are those that exist between the executive and the legislature; Parliament and the people; UK and devolved institutions; and the UK and the EU.

The executive and the legislature

The first of that quartet is the one most obviously implicated by Miller, given that the relationship between legislation and prerogative power is ultimately a function of that between the Crown-in-Parliament and the Crown-as-executive — the latter relationship being shaped at the most basic level by the doctrine of parliamentary sovereignty. From that doctrine, certain fundamental propositions ineluctably follow — the paramount proposition being that Acts of Parliament take priority over the royal prerogative when the existence or exercise of the latter would conflict with the former. For all that Miller has invited debate and disagreement, no-one seriously questions that proposition. But that gets us only so far. The basic proposition merely determines the priority rule that applies when relevant circumstances arise. However, that does not, in itself, answer the prior question as to what those circumstances are. That, in turn, requires us to move beyond the fact of the priority rule and to engage with the more subtle questions: how long is the shadow cast over executive authority by parliamentary sovereignty, and hence over the prerogative by legislation?

For instance, to what extent does that shadow extend beyond scenarios in which statute specifically colonises territory previously occupied by the prerogative, to situations in which the exercise of a prerogative power may impact upon or otherwise affect, directly or indirectly, some arrangement that has been fixed in place by Act of Parliament? A distinct, but connected, question is whether the principle of parliamentary sovereignty provides any assistance when it comes to interpreting legislation that might or might not be construed as having fixed in place an arrangement that would be trespassed upon if the executive were permitted to deploy the prerogative. Does it, for instance, help us to determine whether the European Communities Act 1972 is constitutive of domestic statutory rights or a merely ‘ambulatory’ conduit for EU law rights? Does the sovereignty doctrine assist in determining whether the ECA ruled out the use of the prerogative for the purpose of achieving Brexit and (if so) whether the European Union Referendum Act 2015 might be read as removing that inhibition? Does it help us to resolve questions about what inferences, if any, should be drawn from textual legislative silence on pertinent matters?

The extent to which the sovereignty principle is helpful in relation to, or dispositive of, such questions must turn, at least in part, on what we understand that principle to be. As foreshadowed, at its core lies the (apparently) simple priority rule that legislation enacted by the UK Parliament takes precedence over conflicting norms. But that is not particularly helpful if, in the first place, we are uncertain about whether Parliament has put in place arrangements of a type that cannot lawfully be disturbed by the prerogative, or if we are uncertain whether, in making such arrangements, Parliament has preserved (or revived) prerogative authority to do things that may affect them. Sovereignty of course demands that Parliament must get its way, but that bald proposition does not in itself enable us to ascertain what it is that Parliament wants in the first place. If, then, the sovereignty principle is to take us further and assist with answering questions such as those outlined in the previous paragraph, it can do so only if we are prepared to derive from it a hinterland of further principles and presumptions.

It was by doing precisely that that the Divisional Court in Miller reached the conclusion that it did. Examining the ECA through the prism of ‘background constitutional principles’ — that is, applying the principle of legality in a particular manner — led the Court to construct Parliament’s intention vis-à-vis the ECA in a particular way, the upshot being that the ECA was taken to rule out the use of the prerogative for the purpose of triggering Article 50. In doing this, the Court took the priority rule that lies at the core of the sovereignty doctrine and inferred from it a further proposition as to the depth of the presumptive stance that courts should adopt when construing legislation in order to determine how it interacts with prerogative power (i.e. whether it abrogates it or renders its exercise unlawful). The Court thus determined the length of the shadow that the sovereignty principle — and hence legislation enacted in reliance upon it — casts over the prerogative, by articulating in relatively strong terms the relevant sovereignty-inspired interpretive presumption that fell to applied. My purpose here is not to argue that the Divisional Court went wrong in doing this. Rather, it is to argue that the conclusions it reached might fairly be said to flow from without being dictated by the sovereignty principle. It follows that if the Supreme Court adopts the same view, then it will be telling us something about the sovereignty principle rather than straightforwardly applying it.

Parliament and the people

A second constitutional relationship implicated by Miller is that which exists between Parliament and the people — and so between the notions of parliamentary and popular sovereignty. The Divisional Court endorsed Dicey’s view that ‘judges know nothing about any will of the people except in so far as that will is expressed by an Act of Parliament’. The latter is linked so closely to the priority rule that forms the core of the doctrine as to be indistinguishable from it: faced with a choice between the ‘will of the people’ and an Act of Parliament, a court (unless it were to repudiate the sovereignty doctrine) would have to prefer the legislation.

But as with other aspects of sovereignty, this does not take us all that far within the context of Miller, the questions raised by it being too subtle to be susceptible to resolution by applying nothing more than the sovereignty doctrine’s core proposition. Putting to one side the unsustainable argument that the referendum straightforwardly trumps the ECA, the real question becomes whether relevant legislation should be interpreted (in the case of the ECA) as leaving undisturbed the Government’s capacity to use the foreign affairs prerogative so as to initiate the withdrawal process — or (in the case of the 2015 Act) as removing any previous disturbance to that capacity. Viewed thus, the priority rule which dictates that courts should not dispense with legislation in the face of contrary popular opinion is not implicated. But what of the penumbral proposition that that judges ‘know nothing of’ public opinion? This, surely, cannot be a cut-and-dried matter. Assume, for instance, that it was accepted that the executive had authority to trigger Article 50 but that a dispute arose as to the lawfulness — and, specifically, the reasonableness — of the exercise of that power. In such circumstances, it would seem odd, to say the least, if the court were to ignore the fact that a referendum had occurred and yielded a given outcome.

Might, then, the fact that Parliament provided for a referendum and that such a referendum took place and yielded the decision it did also go to the legal question whether relevant legislation should be interpreted as disturbing (or reviving) the possibility of using the foreign affairs prerogative to trigger Article 50? Might, for instance, the fact that an exercise of popular sovereignty has taken place lessen the force exerted by parliamentary sovereignty-inspired interpretive presumptions that might otherwise lead to the conclusion that the prerogative remains excluded and unrevived? Is the constitutional mischief — i.e. executive overreach — against which the presumption deployed by the Divisional Court seeks to guard present, or present as acutely, when the prerogative is used to implement the outcome of a referendum? I seek merely to raise, not to answer these questions, here; to point out that they are facets of larger questions about the relationship between parliamentary and popular sovereignty; and to suggest that the need to resolve them is a real one, given that referendums are now a relatively common feature of the constitutional landscape. I certainly do not contend that an exercise of popular sovereignty is or should be capable of turning Diceyan orthodoxy on its head by licensing judges to dispense with legislation. But there is surely a large grey area separating that proposition from the one, lying at the opposite end of the spectrum, which asserts that courts ‘know nothing’ whatever of public opinion.

UK and EU law

It may seem odd that uncertainty should persist about the relationship between Parliament (and its enactments) and EU law, given that the UK has been a member of the EU for several decades, and bearing in mind that it is over 25 years since the House of Lords’ seminal decision in Factortame. And yet the precise nature of that relationship has never been finally settled. What we know for certain is that EU law can prevail over incompatible Acts of Parliament, and that domestic courts are prepared to disapply such legislation. But the reasons why the position is thus are, as a matter of domestic constitutional theory, uncertain. Factortame, in particular, was notably light on detail when it came to explaining the theoretical basis for permitting EU law to take priority. Explanations have, however, been offered, including judicially, the most notable instance being Laws LJ’s judgment in Thoburn, in which the notion of ‘constitutional statutes’ was developed — a notion upon which the Divisional Court placed considerable weight in Miller.

Of course, that case does not raise a straightforward question about the priority of EU and UK law such as the one with which the House of Lords was confronted in Factortame. However, questions about the juridical basis of EU law’s priority over domestic law are arguably far from irrelevant to the issues raised by Miller. One issue, for instance, is whether analogies between the ECA and (other) ambulatory legislative schemes for giving effect to international treaties are doomed to failure because of the special place and status of EU law within the UK legal system — those questions of place and status being inextricably bound up with questions about whether, and if so on what basis, EU law is to be taken to constrain Parliament and thereby impinge upon its sovereignty.

If, for instance, Laws LJ’s analysis is adopted, and the ECA is taken to be a constitutional statute that is immune from implied repeal, then that raises the question whether such legislation should also enjoy particular protection in respect of the use of the prerogative. It also raises the distinct question whether characterising an Act of Parliament as a constitutional statute should be taken to tell us anything about the intention of the enacting Parliament — e.g. whether Parliament in 1972 can be taken to have had any intention about the use of the prerogative in circumstances such as those that have now arisen — or whether it tells us only about the common law’s stance in respect of the legislation. And if EU law’s priority is not to be accounted for by characterising the ECA as a constitutional statute, how is it to be accounted for? And what does that tell us (if anything) about the strength of any presumption that might apply when construing the ECA in order to determine whether it prevents the use of the prerogative for the purpose of terminating the UK’s membership of the EU?

This is not the occasion on which to seek to answer such questions — questions that have been the subject of considerable analysis elsewhere, but which, perhaps improbably, still lack definitive answers. Depending on how one views the issues raised by Miller, questions about the nature and status of EU law as it pertains within the UK’s domestic constitutional order might be considered central — meaning that clear answers to those questions may be required. For that reason, it may be that the Supreme Court will have to engage with the conundrum that has long existed, but which remains authoritatively unresolved, concerning the relationship between the EU primacy doctrine and the principle of parliamentary sovereignty. It would certainly be ironic if our apex court were to engage with and provide clear answers to those questions just as the UK is preparing to leave the EU and denounce EU law’s supremacy. But it is already the case that the sovereignty doctrine’s capacity — somehow — to accommodate EU law’s primacy has told us something — even if we are not certain precisely what it is — about the nature and flexibility of that doctrine. Miller might provide the Supreme Court with an opportunity to tell us rather more — and to illuminate the sovereignty principle in ways that will remain pertinent long after Brexit is finally accomplished.

The UK Parliament and the devolved institutions

The sovereignty doctrine — and the constitutional uncertainties that coalesce around it — is implicated by Miller in a fourth respect. It concerns the relationship between the UK Parliament and the devolved institutions, and thus raises fundamental questions about the meaning and relevance of parliamentary sovereignty within the UK’s newly multifocal territorial constitution. Take, for instance, the questions that Miller raises in relation to the Sewel Convention. As Aileen McHarg has pointed out, if the Divisional Court’s logic were to be applied in this context, the Convention might well be considered applicable. If prerogative authority to trigger Article 50 does not exist, meaning that legislation is required, any such legislation would — thanks to the ECA’s status as a ‘constitutional statute’ — have to confront explicitly the implications for that Act of triggering Article 50. The same might therefore go for devolution legislation like the Scotland Act 1998, which is also a ‘constitutional statute’. As McHarg acknowledges, that Act ‘would be less centrally affected by withdrawal from the EU than the ECA’. But the point is at least arguable: as she observes, ‘EU withdrawal would have significant direct and indirect effects on the scheme of devolution established by the [Scotland Act]’.

My purpose here lies not in examining the detailed technical arguments about whether the Sewel Convention would or would not be engaged by the triggering of Article 50. Rather, my purpose is to highlight the way in which two sharply contrasting visions of the UK constitution collided in the arguments that were presented to the Supreme Court. In its written argument, the Scottish Government unsurprisingly placed considerable weight on the Sewel Convention, arguing not only that it is engaged in the present circumstances but that it forms a ‘constitutional requirement’ within the meaning of Article 50, such that a failure to comply with the Convention would mean that the UK had failed to comply with Article 50. Meanwhile, the Welsh Government argued that the prerogative cannot be used to trigger Article 50 because that would entail the ‘short-circuiting’ of the Sewel Convention. In order to avoid such circumvention (the argument runs) the matter must be one for the UK Parliament — which must, thanks to the Convention, engage in dialogue with the devolved legislatures before deciding whether to authorise the triggering of Article 50. Unsurprisingly, the UK Government’s analysis contrasts with the positions staked out by the Scottish and Welsh Governments. In oral argument, the Advocate General for Scotland insisted that the Convention could not be considered a constitutional requirement for the purpose of Article 50. And he made the ongoing supremacy of the Westminster Parliament a central plank of his case, referring to its ‘absolute sovereignty’ and saying that section 28(8) of the Scotland Act 1998 — which was inserted by the Scotland Act 2016, and which acknowledges the Sewel Convention — is no more than ‘a self-denying ordinance expressed by a sovereign Parliament … in qualified terms’.

These arguments do not amount to a bald disagreement about whether Westminster remains sovereign. The Scottish Government, for instance, acknowledges that ‘the courts could not decline to recognise the validity’ of UK legislation enacted in breach of the Sewel Convention. And of course the Scottish and Welsh Governments’ positions ultimately seek to emphasise the primacy of the UK Parliament’s legislative role over the UK Government’s prerogative authority — positions that are not themselves incompatible with, and are in certain respects bolstered by, the sovereignty of Parliament.

Yet the positions adopted by (on the one hand) the UK Government and (on the other hand) the Scottish and Welsh Governments certainly reveal contrasting readings of the wider constitutional environment within which the (sovereign) Westminster Parliament now sits. As already noted, the UK Government’s position rests upon a highly traditional understanding of parliamentary sovereignty, according to which the Sewel Convention — section 28(8) of the Scotland Act notwithstanding — can be nothing more than a political consideration. This requires the UK Government to occupy the uncomfortable position that section 28(8), which of course it caused to be enacted by the Westminster Parliament, is legally meaningless. In contrast, the Scottish and Welsh Governments’ views underline the way in which devolution has caused the tectonic plates of the constitution to shift, such that the sovereignty of the Westminster Parliament falls to be viewed through a constitutional lens that blurs the distinction between legal and political analyses of the British constitution. On this view, the significance of the fact that the UK Parliament remains legally sovereign can be understood only against the backdrop of the constitutional parameters that are set (among other things) by the Sewel Convention. On this view, for the UK Parliament to legislate in breach of the Sewel Convention might be ‘lawful’, but it is not ‘constitutional’.

Final thoughts

The doctrine of parliamentary sovereignty sits at the heart of the UK constitutional order. On one level, it lends the constitution a beguiling simplicity: whatever Parliament enacts is the law, and whatever conflicts with Parliament’s law is invalid. On another view, however, the sovereignty doctrine is little more than a veneer that (barely) conceals profound constitutional uncertainty and controversy. The ultimate controversy, of course, concerns whether the proposition at the core of the doctrine holds true: might the courts — as some of the Law Lords in Jackson hinted — decline to uphold legislation that committed a full-frontal assault upon a fundamental constitutional right or value?

That question is not one that is raised by the factual matrix of Miller. But that is not to deny that questions — albeit more subtle ones — about the nature of parliamentary sovereignty are implicated by the case. Beyond its core proposition, the nature, significance and contours of the sovereignty principle emerge relationally. I have made that point elsewhere, in my analysis of the Evans case, in respect of the interoperation of the sovereignty, rule-of-law and separation-of-powers principles. Miller reveals other aspects of the relational nature of sovereignty, by drawing our attention to its interactions with executive authority, popular sovereignty, international (and, in particular, EU) law, and the UK’s multifocal territorial constitution. Each of these relationships raises fundamental constitutional questions to which straightforward answers are unavailable. In deciding Miller, the Supreme Court will not therefore simply be ‘applying’ the doctrine of parliamentary sovereignty: it will be illuminating its character, and in doing so it may tell us something quite profound about the nature of the contemporary British constitution.