I have been following an interesting debate on Twitter, triggered in part by this recent post, concerning the amendment of the Ministerial Code. Until earlier this month, the Code said in paragraph 1.2:

The Ministerial Code should be read alongside the Coalition agreement and the background of the overarching duty on Ministers to comply with the law including international law and treaty obligations and to uphold the administration of justice and to protect the integrity of public life

Now paragraph 1.2 says:

The Ministerial Code should be read against the background of the overarching duty on Ministers to comply with the law and to protect the integrity of public life.

The new version thus makes no reference to any obligation upon Ministers to comply with international law (including the UK’s treaty obligations). The Cabinet Office says that it is, in effect, merely saving words: “The code is very clear on the duty that it places on ministers to comply with the law. ‘Comply with the law’ includes international law.” However, this stretches credibility: against the background of the Conservative Party’s 2014 policy document concerning the European Convention on Human Rights, which said that the Ministerial Code would be redrafted “to remove any ambiguity in the current rules about the duty of ministers to follow the will of Parliament in the UK”, it is tolerably clear that the recent change to the Code is about more than simply economical drafting. This prompts three comments.

First, as has been argued elsewhere, is has always been the case that Ministers’ primary legal obligation, as a matter of domestic constitutional law, is to conduct themselves in conformity with Acts of the United Kingdom Parliament, such legislation being the highest form of law recognised in the UK. In this sense, it is arguable that the old version of the Code was misleading. In the same way, the Cabinet Office’s defence of the amendment — which reduces to the bare assertion that Ministers must obey all law — is an unhelpful oversimplification. Indeed, if and when domestic and international law conflict, it merely invites — but offers no guidance as to the resolution of — the question: “Which law?”

Second, this raises fundamental questions about the relationship between different types of legal norms. Within a domestic legal system, different norms subsist within an essentially hierarchical relationship. Acts of the UK Parliament trump the common law. UK legislation enjoys priority over devolved legislation. And, now, constitutional legislation has a form of priority over ordinary statutes. Matters become more complex, however, when we consider the relationship between domestic and international norms (as distinct from the relationship between different forms of domestic norms). In some legal systems, such matters are resolved by constitutional rules that ascribe priority to international over domestic law. Not so, however, in the UK. Here, instead, we encounter two apparently contradictory legal claims: a claim made by the UK Parliament to the effect that its enactments are legally unquestionably on account of parliamentary sovereignty; and a claim made by international law to the effect that it is binding upon States.

In this way, an impasse is reached: from a domestic-constitutional perspective, Parliament is sovereign; but from an international-law perspective, international law is binding upon the UK notwithstanding the domestic-legal sovereignty of the UK Parliament as a domestic institution. However, while it may appear that conflicting claims are being made about who calls the shots, the reality is that these claims concern parallel legal or constitutional dimensions, such that those who emphasise one or other of the claims end up arguing past one another. In fact, there is no contradiction involved in subscribing to the doctrine of parliamentary sovereignty whilst espousing the binding force upon States of international law. This is so because ultimately these two elements of legal doctrine inhabit different — domestic and international — legal dimensions. Whilst it would be incoherent for a single legal order to acknowledge two sovereign sources of legal authority (for instance, the Westminster Parliament and the Scottish Parliament cannot both be sovereign so long as Scotland remains within the UK), the same is not true when we consider the interaction of distinct legal orders (such as the UK and the international legal orders).

Third, how should this analysis inform our assessment of the recent changes to the Ministerial Code? To the extent that the new version may be considered to imply that Ministers are not obliged to abide by international law, it is correct as a matter of domestic law. It is also correct as a matter of international law, in that international law generally imposes obligations upon States themselves rather than upon particular institutional actors within a State. Indeed, it is for this reason that Parliament, as a domestic institution, can be said to be sovereign — and hence to have the domestic-legal capacity to breach international law — even though the UK as a State is required to abide by international law. However, this analysis only gets us so far. It may be true that UK Ministers, like the UK Parliament, are free as a matter of domestic law to breach international law. But any sort of joined-up approach to questions of legality must confront the capacity of UK constitutional actors — with administrative or legislative actors — to do things that place the UK in breach of its international-law obligations. And in a constitutional democracy founded upon the rule of law, it is appropriate that constitutional actors with the capacity to place the State in breach of international law should be expected — and, as far as possible, required — to conduct themselves so as to avoid such breaches.

In the end, the matter can be put quite simply. Unless it were envisaged that the UK Parliament would legislate in a way that required or permitted Ministers to breach international law, it would make perfect sense to continue to expect Ministers to abide by international law and to reflect such an expectation in the Ministerial Code. Indeed, through well-established canons of interpretation, the courts interpret legislation, whenever possible, so as to ensure that it is given a meaning that accords with the UK’s international obligations, thereby obviating any need for Ministers to choose between giving effect to obligations that they are under as a matter of domestic law and obligations that bind the UK as a State. On the other hand, relieving Ministers of any obligation in the Code to abide by international law would make perfect sense if it was envisaged that Ministers would be directed by Parliament to do things — such as refusing to give effect to certain judgments of the European Court of Human Rights — that might place the UK in breach of its international-law obligations.

Ultimately, the Ministerial Code is merely a political tool that helps to shape and measure the propriety of ministerial conduct. In this sense, nothing it says has any direct bearing upon questions of legality. Nevertheless, it is an important tone-setting document in constitutional terms, and it is hard to avoid concluding that the excision from it of any reference to international law lays the ground for precisely the sort of realignment envisaged in the Conservative Party’s 2014 policy document, whereby the domestic doctrine of parliamentary sovereignty is more aggressively emphasised at the expense of the UK’s international-law obligations. The domestic legality of such an approach should not however blind anyone to the fact that it would amount to a repudiation of the rule of law if (as it should) that principle is understood as requiring States to abide by international law just as it requires domestic governmental actors to abide by domestic law. To the extent that this duality in the rule-of-law notion risks presenting Government Ministers with an impossible dilemma, it implies an obvious (if paradoxical) requirement: that the UK Parliament, for all that it may be “sovereign”, ought to resist any temptation to exercise its law-making power in a way that would in the first place confront the Executive branch with such a conundrum.