In my recent paper for Politeia, I show that, since its inception, the European Court of Justice (ECJ) has never been an impartial court in disputes between the EU and its Member States or indeed between the EU institutions and other bodies or international entities. In these circumstances it is hard to believe anyone could consent to continued post-Brexit ECJ jurisdiction: why would the ECJ treat the UK any better or at all fairly once the UK is no longer a Member State? The ECJ’s pro-Union legal interpretation is rooted in its own conception of its role as an EU institution committed to further integration which is brought to bear on its distinctive ultra-flexible approach to treaty interpretation. The general rules of treaty interpretation are set out in Articles 31 and 32 of the Vienna Convention on the Laws of Treaties (“VCLT”). The Vienna Convention is not free from uncertainty and it does refer to the context and the objective as aids to textual interpretation. However, Art 31 VCLT emphasises the crucial importance of the ordinary meaning of the treaty text, and that the words of the text must be interpreted in good faith. If this means anything at all, it must mean that purposes cannot simply be read into the text and that the text itself is the primary guide to meaning and purpose. Only if there is real uncertainty, should other interpretative criteria be applied. The EU is not a signatory to the VCLT. However, almost all its Member States have signed the Convention. Indirectly, therefore, the EU and the ECJ too are under an obligation to follow its provisions. The ECJ has summarised its interpretative approach in Merck v Hauptzollamt Hamburg-Jonas as follows: …in interpreting a provision of [Union] law it is necessary to consider not only its wording, but also the context in which it occurs and the objects of the rules of which it is part. At first sight the ECJ’s own position appears to echo Art. 31 VCLT. But the reality is very different. The ECJ, to my knowledge, has mentioned the VCLT only twice in the tens of thousands of judgments it has handed down over the last seventy years, but on at least one of those occasions went on simply to ignore the Convention’s approach. First, although the ECJ frequently refers to the words used in the legal instrument it interprets, this in itself establishes little. The ECJ cites the text in a perfunctory manner and without proper textual analysis. Crucially, compared to many other courts, the ECJ is more likely to give priority to purposive criteria over linguistic criteria. Second, the ECJ extremely rarely uses historical arguments. Third, amongst the purposes the ECJ relies on, it liberally includes meta-teleological criteria. Meta-teleological arguments refer to general ‘umbrella purposes’ which may not even be written into the treaty. For example, the ECJ has referred to the ‘spirit of the Treaties’ in dozens of cases. The spirit has an established place in Hegelian philosophy – legal certainty, however, spiritual guidance promotes not. Fourth, EU law has no doctrine of the ratio decidendi. Any ECJ decision, and indeed any statement on the law, may effectively become a precedent. The importance of de facto precedents in the ECJ’s argumentation is illustrated by the fact that there is now hardly any case in which the ECJ does not refer to at least one previous decision. In referring back to its own case law, the ECJ implicitly also relies on meta-teleological considerations and the body of precedents itself acquires a communautaire — or pro-Union — flavour. Over time the Treaties in this manner acquired a distinctly more integrationist flavour than their wording suggests. Moreover, the appeal to previous decisions enhances judicial credibility in the sense it suggests judicial objectivity and creates the impression that the court did not exercise a choice but instead reached its decision subject to the constraints of legal consistency and certainty. The appeal to precedent also lends later decisions the aura of legal objectivity, simply because in analysing a case not every relevant previous case is excavated and subjected to legal analysis. Fifth, The ECJ’s variable or cumulative approach, combined with its meta-teleological dimension, gives its decision-making a distinctive pro-Union communautaire tendency: a predisposition, in other words, to resolve legal uncertainty in favour of further integration. Reliance on precedents then solidifies and reinforces the ECJ’s communautaire leaning. Finally, the ECJ operates in an extremely permissive political and judicial environment. ECJ judgments can be overruled only by the ECJ itself or by unanimous treaty amendment by the Member States. In these circumstances general acceptance throughout the EU of the ECJ’s activist and integrationist approach to treaty interpretation means that the ECJ acquires a de facto power of amending and extending the EU’s quasi-constitution. The ECJ’s communautaire predisposition tends to be irrelevant in most run-of-the-mill cases, which concern the application of more or less clear, detailed and technical provisions. Examples of these are agriculture, customs union, and tariff cases. By contrast, the areas of substantive law where the Court’s integrationism has been most evident are the internal market, free movement of persons, asylum and the euro rescue cases and those concerning the relationship of EU law to national law on the one hand and international law on the other. Most relevant here is the Court’s pro-Union decision-making in the field of international agreements, about which the following points should be made. First, the ECJ has ensured the supremacy of EU law over potentially conflicting international law by transposing large chunks of international law and then asserting its own jurisdiction to interpret and give effect to international law on its terms – an approach which may be called ‘the strategy of incorporation’. This has allowed the ECJ either to give effect to international law when it suits it – for example, to extend its own jurisdiction to review national law for compliance with obligations under international treaty and customary law – or to circumvent, qualify or ‘adapt’ the effects of international law on the EU legal order by interpreting EU law ‘autonomously’, i.e. without reference to precedents or guidance laid down by other international courts. Second, whilst the ECJ has not questioned that international agreements entered into by the EU or so-called mixed agreements may be used by individuals to challenge national law, it has generally adopted a ‘dualist’ approach and resisted the direct effect of provisions of international agreements in actions challenging the legality of EU legal acts. Third, in the case of Van Parys the ECJ went so far as to deny binding status to WTO dispute settlement body decisions in EU law. Fourth, the ECJ has jealously guarded its own autonomy and judicial pre-eminence over the interpretation of every aspect of EU law both in relation to the extension of EU law to the EEA Agreement (Opinion 1/91) and in its more recent Opinion 2/13 concerning the accession of the European Union to the ECHR. More recently, it has done so even in relation to arbitration clauses governing bilateral investment treaties between Member States, which the Court declared invalid in the recent Achmea decision. Fifth, it is thus all the more surprising that in the area of free trade agreements between the EU and other countries the ECJ recently adopted a more relaxed approach to safeguarding its own jurisdiction. In Opinion 2/15 concerning the Free Trade Agreement (FTA) between the European Union and the Republic of Singapore, the Court declared binding dispute settlement by a bilateral arbitration panel procedure compatible with EU law. Let me sum up: The EU’s insistence that a free trade agreement requires final dispute resolution by the ECJ is spurious and at variance with the ECJ’s case law regarding the legality of, for example, the EU-Singapore trade agreement. The UK has nevertheless accepted ECJ supervision in the proposed Agreement. Apart from the fact that it is degrading for a sovereign nation to submit itself in bilateral treaties to the jurisdiction of the domestic court of the other side, I hope I have demonstrated that the ECJ will never be an impartial arbiter in disputes between the EU and other parties – including former members. It is not even impartial in respect of EU members. How may it be assumed that post-Brexit the ECJ would accord the UK even the very minimal respect it currently pays EU member states? Whatever the British people may have had within their contemplation when they voted for Brexit in June 2016, it surely included the conviction that the UK should not remain subject to an imperial foreign court.