Professor Finnis posed a powerful challenge to the Miller decision by contending that the claimant’s argument was based on the following syllogistic fallacy. (1) Statutory rights enacted by Parliament cannot be destroyed by executive action without Parliamentary statute. (2) The rights acquired by UK persons under the Treaties given effect in the UK by s. 2(1) ECA 1972 are statutory rights enacted by Parliament. (3) Therefore no executive action can be taken to terminate the UK’s adherence to those Treaties without authorization by statute.
John Finnis postulated what was in effect an alternative syllogism. (1) It is only statutory rights created by Parliament that cannot be changed by executive action without Parliamentary statute. (2) EU rights are not in that sense created by Parliament; there must be a statute to authorize application of EU rights in UK law, but that is the mere conduit for rights created through the Treaty and norms made thereunder. (3) It follows therefore that the executive can terminate our membership of the Treaty pursuant to the prerogative without seeking prior statutory authorization. There are however difficulties with this alternative syllogism.
First, proposition one is contingent, not a priori. There is a conceptual difference between rights that owe their existence to a UK statute and those that have an existence independently thereof through an international treaty. There is, however, no logical reason why the fact that the rights are derived from a Treaty leads to the conclusion that the executive should be able to act alone and extinguish those rights. This cannot even be regarded as the default position, since it is inconsistent with the Constitutional Reform and Governance Act 2010, which embodies the default principle that the House of Commons can prevent the government from ratifying an international treaty of which it disapproves, and with the default principle that the statute through which the Treaty rights have been incorporated must be duly repealed by a UK statute. It is moreover an axiomatic proposition that rights that owe their provenance to a treaty nonetheless take effect in UK law as domestic rights pursuant to the statute that gave effect to the treaty in UK law, a position reinforced by the European Union Act 2011, s 18.
Second, propositions one and two are based on contestable normative assumptions. It may be entirely fortuitous whether Parliament chooses to create certain rights in a free-standing UK statute, or whether it embodies them through adherence to an international treaty that contains the same rights, which are then given effect in the UK through a statute. It would be constitutionally arbitrary that the executive’s power to alter these rights should depend on which route is taken, and it is very doubtful whether Parliament would think differently of the rights made part of UK law in these two ways. This is more especially so since the rights contained in the UK statute may well have a mixed provenance, being dependent in part on pure domestic law, in part on international treaty and in part on EU law.
Third, proposition three does not follow inexorably from propositions one and two. The fact that rights recognized in a UK statute flow from a treaty does mean that they may cease to exist in the UK if they are altered in accord with the Treaty, and this can occur without specific parliamentary authorization for the particular change. Thus, the scope of EU citizenship rights expands or contracts in accord with changes in Treaty rules, EU legislation and CJEU decisions. This is duly taken into account through ECA s 2(1), which speaks of EU rights and liabilities that exist from time to time, thereby authorizing in advance such changes as might be made, subject to conditions specified in legislation such as the European Union Act 2011. The executive’s participation in making decisions at the international level that have implications for EU rights that pertain in nation states is, however, dependent on a decisional rule within the international treaty that provides the legal foundation for such participation and for the decisions thereby made, such as a rule about Treaty amendment or the procedures for enactment of EU legislation. The preceding does not, however, inexorably mean that the executive of its own volition can take action that will terminate EU membership and associated rights without parliamentary authorization. To the contrary, there is no decisional rule authorizing this executive action. It is no answer to point to Article 50(1) TEU, and claim that this is the requisite decisional rule that provides the legal foundation for its autonomous action, since it is the very interpretation of the UK constitutional requirements under Article 50(1) that is in issue, viz whether the executive can act in this autonomous manner.
Fourth, the distinction between rights created directly by a UK statute and those that owe their origin to a Treaty should not be determinative of this dispute, irrespective of whether Article 50 once triggered is irrevocable. If Article 50 is revocable then its triggering does not ipso facto take away the rights of the parties, but signals the beginning of the negotiation, and thus the distinction between the two species of right is not relevant. If Article 50 is irrevocable then the distinction should also be irrelevant, since it is unsound in terms of normative principle to allow the executive alone to make the decision that is wholly determinative of the rights associated with our EU membership.