Miller and Northern Ireland: A Critical Constitutional Response

Abstract

The Miller case, decided by the UK Supreme Court in January 2017, considered the legality under UK law of the use of the royal prerogative to trigger Article 50 TEU and begin the process of the United Kingdom ("UK") leaving the European Union. The Miller case involved two constitutional questions of fundamental significance concerning the government's claim to be able to use unfettered executive power under the royal prerogative to trigger Article 50. The first concerned the implicit reversal, as a result of triggering Article 50, of the constitutional decision embodied in the European Communities Act (ECA) 1972. The second concerned the implicit reversal, also as a result of triggering Article 50, of the constitutional decisions regarding Northern Ireland and Scotland, embodied in the devolution acts and (as regards Northern Ireland) in the Belfast-Good Friday Agreement. This chapter argues that Miller correctly provided a robust defence of Parliamentary authority in connection with the ECA 1972, and adopted a nuanced understanding of the constitutionally-grounded relationship between the UK and the EU, rejecting the claim to unfettered executive power exercised under the royal prerogative. However, when it came to the devolution issues, the Court unfortunately proceeded to deploy a very traditional, and rather blunt, understanding of the principles of British constitutional law, including Parliamentary sovereignty. This chapter argues that the devolution aspects of its judgment in Miller will come to be seen as a significant misstep, in that it failed to live up to the challenge of becoming a truly constitutional court for the UK as a whole. With a focus on Northern Ireland, the chapter explains how critically important questions of constitutional law were ignored entirely or decided in undue haste. Indeed, the UK Supreme Court gave every indication that the devolution aspects of the litigation were a diversion from what it considered the "main" issue regarding the ECA 1972. In deciding the devolution issues, the most orthodox possible understanding of the principles of British constitutional law were drawn on to override any more nuanced understanding of constitutional developments relating to Northern Ireland. No doubt unintentionally, the Court adopted a view of the British constitution at odds with what is required to accommodate Northern Ireland's evolving constitutional development, potentially undermining the Belfast-Good Friday Agreement.

Keywords: Brexit, Northern Ireland, Supreme Court, Article 50 TEU, Royal Prerogative, devolution