The decision of the Supreme Court in Cherry / Miller (No.2) [2019] UKSC 41 has been heralded as a significant moment in our constitutional history, a case which will be regarded as a defining part of the fabric of our constitution for centuries to come.  Whether it will live up to this billing is a matter for the future, yet this case might easily be understood to confirm a major shift in UK constitutional law.  In particular, the decision that the Prime Minister’s five week prorogation of Parliament at a crucial moment in the Brexit process was unlawful raises significant questions about the UK’s ‘political constitution’.

From one perspective, the intervention of a unanimous panel of eleven Justices of the Supreme Court to overturn the Prime Minister’s decision might signal ‘the dissolution of the old political constitution’, as Colm O’Cinneide has maintained.  Alternatively, it can be argued that there is ‘nothing in the substance of the judgment with which a political constitutionalist could disagree’, as suggested by Richard Bellamy.  There is much to be said for both of these positions, yet in this post I want to try to explore further the implications for the political constitution.  The Cherry / Miller (No.2) decision will almost certainly have an impact on the UK’s constitutional model.  While there is a risk of overstating or oversimplifying the implications of the Supreme Court’s judgment in examining its impact on the political constitution, in my view this approach provides a more useful way to begin to assess this case than rehashing arguments (now irrelevant) about whether or not it was right for the courts to intervene in these circumstances.

The challenge in making a clear assessment of the impact of Cherry / Miller (No.2) derives from the complex position of the courts in a political constitution, which classically emphasises political power and mechanisms of accountability, while retaining a more reserved (yet still important) role for judicial oversight.  This constitutional model is of course contested, and has been in flux for a number of decades, with increasing legal limitation of power through the evolution of judicial review, membership of the EU, and statutory constraints in the Human Rights Act 1998 and devolution legislation.  The courts’ oversight of the relationship between Parliament and the government established in Cherry / Miller (No.2) could be understood as a continuation of this trend, or as evidence that the political constitution has adapted, and its values have permeated the judicial process.  Alternatively, the Supreme Court’s decision might have mixed constitutional consequences: the case may promote significant substantive political values, while generating doubts about the legal claims which underpin them.

Constitutional Principles and the Political Constitution

The Supreme Court’s judgment is framed around two constitutional principles of central importance in the political constitution: parliamentary sovereignty and the accountability of government to Parliament.  These principles are taken together to establish a limit on the scope of the royal prerogative power to prorogue Parliament, which cannot be used in a way which has ‘the effect of frustrating or preventing, without reasonable justification, the ability of Parliament to carry out its constitutional functions as a legislature and as the body responsible for the supervision of the executive’ (at [50]).  Yet this raises a number of questions.  First, in framing the question as concerning the scope of prerogative power in this manner, the Supreme Court was able to sidestep – rather than engage with – the legal and political difficulties concerning the justiciability in principle of a decision to prorogue Parliament which had been found persuasive by the Divisional Court.  And as Stephen Tierney has shown, that more restrained approach could also have been justified by reference to constitutional principle.

Second, the principle of parliamentary sovereignty is used largely superficially, to provide a gloss on the Supreme Court’s reasoning – it features as part of the general justification for limiting the prorogation power in principle, but then disappears from the analysis of the effects of this particular decision on Parliament’s ability to perform its constitutional role (especially at [55]-[58]).  Instead, the analysis of the legality of this specific suspension of Parliament focuses on the impact on the legislature’s scrutiny and accountability functions.  Yet it unclear where the constitutional principle of parliamentary accountability obtains its legal (as opposed to its political or conventional) force.  The comments of Lord Carnwath in Miller (No.1) as to the fundamental importance of the constitutional principle of accountability are cited (at [46]), yet in that earlier case this principle was used in dissent, to support the argument that judicial oversight of the relationship between Parliament and government was not necessary.  As a result, the judgment gives the impression that parliamentary sovereignty, a doctrine with unquestionable legal status, is simply deployed to establish the claim that this prerogative power can be limited as a matter of law (at [44]), even if in substance the main effect of this prorogation is to disrupt the operation of an important, but much less obviously legal, constitutional principle.

A third challenge in the relation to the compatibility of the Supreme Court’s judgment with ideas of political constitutionalism is the way in which the judicial role is characterised:  ‘the courts have the responsibility of upholding the values and principles of our constitution and making them effective’ (at [39]).  There is little sense that this is a shared task with the political institutions, which is reinforced by the court’s dismissal of Parliament’s essential role in approving public spending as a ‘practical constraint’ which offers ‘scant reassurance’ (at [43]).  The court is similarly robust when quashing the Order in Council which had approved prorogation, and all the steps which flowed from it, including the acts of the Lords Commissioners within the House of Lords: ‘it is for the court and not for Parliament to determine the scope of Parliamentary privilege’ (at [66]).

When considering these challenges, we must appreciate that this judgment was written with impressive haste given the dramatic political circumstances, while also most likely framed in such a way as to attract the widest possible support among the unanimous Justices (an extremely significant fact in its own right).  Yet the sweeping use of constitutional principles which is the most notable feature of this judgment is also not new, but part of a broader trend which sees the role and position of the Supreme Court changing.  Even when the constitutional values which the courts are promoting are ones which are fundamental to the operation of our democratic political system, there are still independent questions to ask about the implications of accepting the judiciary as the articulators and enforcers of these principles.

Constitutional Context and the Political Constitution

While there are therefore reasons for scepticism about the reasoning of the Supreme Court, the Cherry / Miller (No.2) decision must equally be understood in broader constitutional context.  As the court explicitly noted, this case can be viewed as a ‘one off’ (at [1]).  The circumstances in which it was heard are exceptional, with the current government acting with a remarkable disdain for democratic values in attempting to shut down a Parliament opposed to its policies, during a time limited period when meaningful attempts to force the government to change course were planned.  When a government attempts to act in a way which cuts across accepted norms of constitutional conduct and collapses parliamentary accountability, it is unsurprising that it provoked a more expansive (and more unified) judicial response than might have been expected in normal times.

It is also significant that this executive overreach came from a minority government with a tenuous hold on the confidence of the House of Commons, and therefore on its office.  An attempt at prorogation for such an extensive period at such a critical time would not have been necessary for a government with a clear majority and mandate.  Moreover, the strategic unwillingness of the opposition parties to provide the current Prime Minister with the general election he desires through a vote of no confidence, at least until the prospect of ‘no deal’ Brexit is less immediate, temporarily negated the primary political sanction which the constitution provides for Parliament to bring down a government pushing past the boundaries of its authority.  Nor has the government’s respect for the legislature to which it is constitutionally accountable been in any way reset in the aftermath of the Supreme Court’s decision, with the Attorney General Geoffrey Cox castigating it as a ‘dead Parliament’ with ‘no moral right to sit’ on the day it reconvened after the failed prorogation.

Far from making judicial intervention illegitimate, it is this political context which explains the outcome in the exceptional circumstances of this case.  Rather than representing the end of the political constitution, this episode demonstrates the enduring relevance of a political understanding of the manner in which the constitution operates.  Yet if this decision exhibits a relatively conservative constitutional approach, it also poses a clear challenge for the political constitution in the future.

The Future of the Political Constitution

If it is an exceptional case in exceptional circumstances, we should be cautious in regarding the prorogation case as a big bang moment in UK constitutional law, high profile though it has obviously been.  Indeed, it is arguable that the Cherry / Miller (No.2) decision may not even be most significant constitutional event this month, given in response to the threat of prorogation, opposition and backbench MPs combined to take control of business in the House of Commons, and legislate in just three days to place the Prime Minister under an obligation to pursue a course of action to which he is explicitly opposed.

The product of this activity, the European Union (Withdrawal) (No.2) Act 2019, suggests that Parliament is obviously capable of exercising its own sovereignty to ensure the government must act in conformity with its wishes.  Given the Prime Minister seems ambivalent at best about whether he will comply with this palpably clear legislative instruction, the courts may yet be required to intervene again – such a decision would, without any ambiguity, be one in support of parliamentary sovereignty, the fundamental principle of the political constitution.

Yet it would be quite wrong to be complacent about the current health of the UK’s political constitution.  That we now have a judicial authority on improper prorogation highlights the urgent need for constitutional reform.  This is the case in quite specific terms, in relation to now contentious royal prerogative powers, whether relating to prorogation or (for example) the legislative formality of royal assent.  Yet the need for reform is also evident more broadly – if this episode highlights the end of a political constitution based on elite consensus and cosy respect for the rules of good government, it also shows that the political constitution needs to be reimagined, rather than for political actors to rely on litigation and the judiciary to settle their disputes.

Political reform is required to strengthen the constitutional mechanisms and practices of accountability, but also to open up space for new, more effective democratic inputs and institutions – certainly, something more far-reaching is required than merely codifying and entrenching the current dysfunctional status quo.  In the current period of constitutional overload, none of this will be easy.  Yet this ought to be the legacy of the prorogation case.

Mike Gordon, Professor of Constitutional Law, University of Liverpool

(Suggested citation: M. Gordon, ‘The Prorogation Case and the Political Constitution’, U.K. Const. L. Blog (30th Sept. 2019) (available at https://ukconstitutionallaw.org/))