In the aftermath of the Miller 2/Cherry judgment, delivered on 24 September 2019, the Supreme Court has come under attack for making a ‘political’ intervention. This had led to some calls for political supervision of judicial appointments on the basis that the Supreme Court is now a ‘political player’. In reality these arguments do not seem to have gained much traction but these criticisms, nevertheless, raise some important questions about the boundaries between law and politics in the UK.

The core of the task facing the Supreme Court in Miller 2/Cherry was to interpret and apply constitutional and legal principles. One of the striking aspects of the judgment is the forthrightness with which the justices set out their collective view about how the constitution should be interpreted. The Supreme Court’s judgment stated in clear terms that the separation of powers is fundamental to how the UK constitution operates. What I want to address here is whether it is right to say that the court’s approach to constitutional interpretation was political and therefore problematic.

My basic starting point is that all exercises of constitutional interpretation, when undertaken by a constitutional actor, are political. It is obvious but worth stressing that within the judiciary, and as well as within government and Parliament, there are conflicting views about the meaning of constitutional principles and how they should apply in particular contexts. I do not think it is possible to regard such questions as being purely ‘legal’ and to be entirely divorced from political judgments. For example, whether or not you believe that parliamentary sovereignty is relevant to the question of prorogation is likely to be informed by broader constitutional perspectives which are inherently political.

One should not single out the Supreme Court’s judgment as unusually political. The High Court’s judgment in R (Miller) and others v The Prime Minister [2019] EWHC 2381 (QB), and the way it approached the key questions of constitutional interpretation, was just as political as the Supreme Court’s judgment insofar as it relied on, and set out, a clear view on how the constitution should operate. In a sense, this reveals that the problem with characterising a judgment as ‘political’ is that there is no agreed definition of what the term means in this context. More often than not this accusation is used as a proxy for: ‘I do not agree with the conclusions reached by the court.’

Part of the problem is that the high-profile nature of the case and the circumstances of Brexit encourage an overly hasty conclusion that the Supreme Court’s judgment is abnormally political. However, there is also a more considered view that by deciding to articulate a legal test to apply to prorogation, the court made an inherently political decision to intervene. In response, I would argue that to characterise this form of politicisation as problematic is wrong. The independence of the judiciary does not mean that judges cannot take political positions on the meaning of the constitution. On the contrary, this is part of the core constitutional role of the courts; constitutional interpretation necessarily involves political judgments on the meaning of constitutional principles and the nature of institutional relationships.

A useful analogy can be drawn with the role of the Speaker of the House of Commons. The current Speaker has been repeatedly criticised for an ‘activist’ approach to interpreting procedural rules. However, the Speaker has defended himself on the basis that he must interpret the rules in line with his view of their underlying purpose to ensure that Parliament’s pre-eminent constitutional role is upheld. So the current Speaker’s approach is not unduly political: constitutional interpretation is inherently connected to underlying political perspectives on the constitutional functions of the relevant institutional actors. A different Speaker may well have taken a more conservative approach to interpreting the standing orders, but such an approach would also be based on a political judgment.

Constitutional actors make difficult political decisions on the basis of interpretative judgments on a regular basis. It is a core part of their role. The Attorney General, as the executive’s senior lawyer, will be asked for his legal judgment on all major government decisions with constitutional implications. A leak to Sky News revealed that the current Attorney General, Geoffrey Cox QC MP, had advised the government, when it was being planned, that in his view prorogation from 9 September until 14 October was lawful. That was hardly surprising, especially as the government’s lawyers had made the case at length before the High Court, the Court of Session and the Supreme Court. Many constitutional lawyers who may have been sympathetic to the view that the prorogation was unconstitutional, would have agreed with the Attorney General’s view.

Part of the problem exposed by the critique of ‘political’ nature of the Supreme Court’s, and to an extent the Speaker’s decision, is that Westminster is not used to the government’s constitutional judgments coming under challenge from non-party political actors. In essence, Westminster is not used to constitutional politics, especially where the checks and balances are empowered vis-à-vis the government. The difficulty is that the ‘political’ critique of the court exposes that there is a widespread, and in my view mistaken, view of how our constitution works, with a sharp dividing line between the party political divisions in Parliaments and everything outside that, including the courts, being a politics free zone.

Part of the reason for this situation is the government’s unwillingness to outline the legal and constitutional reasoning behind its decisions. The convention that the Law Officers’ advice is not to be disclosed outside government is a factor. This approach, where the contestability of the constitutional and legal judgments is internalised within government has consistently been shown to be unsustainable in the context of Brexit.

A recent example of this has been the government’s refusal to reveal its own interpretation of the Benn Act (the European Union (Withdrawal) (No. 2) Act 2019). The government has repeatedly suggested that it has found a way of complying with the legislation and leaving without a deal on 31 October 2019. Whether or not this proves to be true, or is merely strategic posturing, it is emblematic of the government’s approach to major constitutional questions throughout the Brexit process.

Minority government and dramatic constitutional change requires, in my view, the government to take a much more open approach to the legal and constitutional reasoning that lies behind its decisions. A reticent approach means that there are inevitably steps taken, as in November 2018 in relation to the Attorney General’s advice on the backstop, to force the government to reveal its position.

To conclude, when the constitution is under strain from all sides, it is normal that Parliament and the judiciary are asked to make decisions on questions of constitutional interpretation which are inherently political. It would be wrong, in my view, to characterise the Supreme Court’s judgment as improper simply because it is based on a particular view of the role of the courts and Parliament in the UK’s constitutional order. One of the few positives of the Brexit process is that it has served to expose the myth that party politics is the only political arena in our constitution. Contestable constitutional decisions, which are by definition political, are a routine and necessary part of any constitutional system based on checks and balances.

Dr Jack Simson Caird is Senior Research Fellow in Parliaments and the Rule of Law at the Bingham Centre for the Rule of Law. From 2015 to 2018, Jack was a researcher in the Commons Library.

A version of this article was originally posted on the Judicial Power Project’s website.