*This piece is an extract from a chapter of the same name by Jonathan Clark from ‘Triggering Article 50, Courts, Government and Parliament‘.
On 23 June 2016, the United Kingdom effectively left the European Union: the referendum was a primary act of sovereignty. At first sight, this sentence will be dismissed as merely incorrect, ignorant of and inconsistent with the UK’s constitution. Its argument was implicitly rejected by three senior judges sitting in the Divisional Court in London, ruling on 3 November 2016 that the government needed some form (left undefined) of parliamentary approval before it could lawfully trigger Article 50 of the Treaty on European Union (inserted there by the Treaty of Lisbon, 2007) to begin Brexit. It was to be expected, thought some, that the government would not receive such approval from a Parliament in which Remainers still outnumbered Leavers, and it is still widely believed that ‘Parliament’ (in current implication, the Lords and Commons but not the Crown) has the last word. But the constitutional position is in key respects disputed, and a major political crisis is the possible outcome. How could that be? What are referenda, and what can they do?
Why the constitution was never fixed
The judges and the Remainers relied on the doctrine of ‘the sovereignty of Parliament’, and the expression is a commonplace. Yet this idea is itself an historical construct, not an eternal truth. It was classically expressed in 1885 by that leading constitutional lawyer Albert Venn Dicey (1835-1922), who was recently cited again in the Divisional Court. He had famously contended that ‘The sovereignty of Parliament is (from a legal point of view) the dominant characteristic of our political institutions.’ Dicey’s arguments, invoking such legal giants as Sir William Blackstone (1723-80) and Sir Edward Coke (1552-1634), proved lastingly influential, at least in shaping widespread assumptions.
In this vision, judges merely interpret the law that Parliament passes; judges (the lawyers assure us) are thus rightly unelected and unaccountable. Whichever way the courts decide, for lawyers the legal position is always clear. The lawyers are (rightly) the winners. To say otherwise is to undermine ‘the rule or supremacy of law’.
Dicey was, however, not a neutral observer or an Olympian theorist but a committed Liberal Unionist. Contrary to his teaching on parliamentary sovereignty in 1885, in his edition of 1914 he looked for extra-parliamentary ways of preventing leaders who ‘can control the party machine’ from forcing Irish Home Rule through Parliament in defiance of what he believed was ‘the possible or certain will of the nation’. In this he failed, for parliamentary politics then trumped both law and populist political involvement.
For historians, great constitutional crises (like the civil war of the 1640s, or the Revolution of 1688, or the American Revolution) happen in legal grey areas. Indeed they happen because there are legal grey areas. The notion of an ‘unwritten constitution’ really only responded to the reality that certain areas of law were ill-defined because they were the sites of continuing political conflict. Brexit, in turn, revives old questions of sovereignty exactly because those fraught questions were never completely resolved. The nineteenth-century genre of ‘constitutional history’ once depicted British constitutional change over centuries as the wise accumulation of clearly-definable right answers, as if they were a wall built stone by stone against tyranny and ending in certainty. Historians of political thought and of political action have moved far from those Victorian assurances. They now show us that final agreements are never reached, that outcomes are always ambiguous, and that the tide of events does not flow in only one direction.
Sovereignty is therefore not like a gold bar, which resides in the vaults of one bank or another. Sovereignty can be discerned only by outcomes. It is a matter of opinion who or what holds it, and opinions have long been both diverse and in conflict.
The people always had a role of some kind, expressed in the medieval notion of ‘the community of the realm’; popular approval was powerful in general, weak in particulars. At coronation ceremonies the (carefully selected) congregation was liturgically asked if it would have a particular individual to be king, and dutifully acclaimed him; but however token, this performance symbolised the truth that the tenure of monarchs (and, today, of heads of the executive) is uncertain in the face of popular revulsion. Uncertain, but seldom easily undone: in 1688 popular opinion was divided between James II and the invading William of Orange, and the Dutchman seized the throne by trickery more than by any popular acclaim. ‘Popular opinion’ is impossible to measure; but it can more accurately be sensed when it is defied by those in office. Such circumstances evoke an older and only partly occluded tradition of political argument in the British Isles, contending that sovereignty ultimately resided with ‘the people’.
The monarch as an individual always had authority, legally known as the royal prerogative; but some monarchs claimed to be absolute, others claimed only to be limited monarchs, others again failed to articulate any coherent explanation of their powers. The role of monarchs changed over centuries, but in so far as their authority passed to the Prime Minister, the authority of the executive was never fully defined. It continues to change, ministry by ministry, Prime Minister by Prime Minister.
The two Houses of the Westminster Parliament long had a role; but even there, MPs have sometimes boasted of their accountability to their constituents, sometimes of their principled independence; some were placemen, others sturdy critics of ministerial corruption. Today, the large number of salaried ministerial and junior ministerial appointments calls in question any simple analysis of Parliament as the sole repository of sovereignty, an institution mounting an independent and effective check on the executive. The executive, too, carries much weight. At the present juncture in UK politics, much is made of the idea of ‘parliamentary sovereignty’ by overt or covert partisans of continued UK membership of the EU; but their present usage would carry more credibility if the Remainers in the Lords and Commons had campaigned to resist the steady draining away of Westminster’s authority to Brussels since 1 January 1973. In reality, they did nothing: ‘parliamentary sovereignty’ is a political slogan, not a constitutional verity.
The courts of law also grew to exercise substantial power, but they were never free from political interference and could never be apolitical. On one interpretation, Parliament is still the High Court of the kingdom, as it was in the middle ages even after the law courts divided from the bureaucratic entourage of the monarch: in theory, Parliament can still try alleged offenders by the ancient procedure of impeachment (still a usable procedure in the United States Congress). The sole and arbitrary power of the judiciary in the field of law cannot be taken for granted. Everything changes.
From at least the sixteenth century, a powerful doctrine emerged that sovereignty resided with that legal fiction, ‘the Crown in Parliament’. All states employ legal fictions (one such in the US today ascribes sovereignty to ‘We the People’), but such constructs tend to change their practical meanings over time. This image of ‘the Crown in Parliament’, too, did not explain the relative powers of King, Lords and Commons. Their relative positions continued to fluctuate, and what were once thought of as decisive turning points in history prove, on further historical research, to have been anything but that. William III, after the Revolution of 1688, ruled in an authoritarian manner as James II had done before it. The idea that the Revolution of 1688 clearly and lastingly settled the question of the royal prerogative does not survive historical research.
From the 1720s an English opposition discourse, inaccurately ascribed to Montesquieu, spoke of the ‘separation of powers’ and ‘checks and balances’. But these metaphors did not solve the problem since separation could not be proved, and since balances or imbalances could not be measured: this misconception therefore fuelled conflict more than resolving it. The doctrine does not hold today: ministers regularly circumvent Parliament, seeking to rule by Statutory Instruments as monarchs once sought to rule by Proclamations. Parliament often tamely acquiesces.
The Referendum: an expression of ‘the will of the people’?
The idea that Parliament was ever simply ‘sovereign’ is, then, an historical myth, and so a bad foundation for law. Long neglected, the idea of parliamentary sovereignty has now been revived as political rhetoric. But rhetoric is not a reliable guide to political realities. This is especially controversial since a new procedure has arrived on the scene: the referendum.
Dicey, whose great book was first published in 1885, first wrote of the referendum in a new Introduction to the edition of 1914, but only as ‘a foreign expression derived from Switzerland’, a practice which might possibly be applied in future, and even then meaning, in his account, only a popular ‘veto’ on Bills already passed by both Lords and Commons. But in 2016 the referendum appeared on the political stage in the UK with a far larger meaning, a primary exercise of popular sovereignty in circumstances in which the political class had been unable to solve a problem. We may love it; we may loathe it; but we cannot now escape it.
Like all great constitutional innovations, it was an unanticipated consequence of tactical needs. Harold Wilson’s referendum in 1975 on EU membership was seldom thereafter appealed to as a precedent. But the referendum in 2011 on adopting the Alternative Vote system in general elections, the referendum in 2014 on Scottish independence, and the referendum in 2016 on EU membership together wrought a silent, unplanned revolution, for in each case it might reasonably be argued that the electorate got it right where the political class had collectively failed. A means now exists of giving expression to what can plausibly be called ‘the will of the people’.
 The Lord Chief Justice, Lord Thomas of Cwmgiedd; the Master of the Rolls, Sir Terence Etherton; and Lord Justice Sales. This chapter is not to be read as a critique of these individuals, but as an exploration of the different perspectives on constitutional questions of the disciplines of law and history. It was written before the hearings on the same issues in the Supreme Court on 5-8 December 2016.
 https://www.judiciary.gov.uk/wp-content/uploads/2016/11/judgment-r-miller-v-secretary-of-state-for-exiting-the-eu-20161103.pdf, hereafter cited as ‘The Judgment of 3 November 2016’.
 A. V. Dicey, Introduction to the Study of the Law of the Constitution (1885; 8th edn., London, 1927), pp. 37, 83, 135, 141, 179, 402, 406.
 Ibid., pp. c-ci.
 The Judgment of 3 November 2016, paras 26, 28.
 Dicey, Law of the Constitution, pp. xci-c. Dicey in 1914 was hopeful that the referendum would be ‘a strictly conservative institution’ at a time when ‘Coalitions, log-rolling, and parliamentary intrigue are in England diminishing the moral and political faith in the House of Commons’, p. xcviii. He did not live to see the institution adopted in its present form.