In Bush v Gore (2004) the US Supreme Court stopped Florida’s recount of votes in the presidential election, sealing George Bush’s slim lead. After time for reflection, influential US scholars argued that the case should have been treated as a political question, since the Constitution empowers Congress (not courts) to determine the eligibility of presidential electors. This is a point deserving consideration in the aftermath of Miller (No 2), which, like Bush v Gore, was a fast-tracked case that involved judicial intervention in politics, basic questions of constitutional structure, and suspicions that justices acted for the sake of a favoured political outcome.
The key points of the US political question doctrine are that courts cannot review a decision where (1) the Constitution affirmatively commits it to Congress or the President or (2) there are no judicially discoverable and manageable standards for ruling on the issue (see Baker v Carr (1962)). The roots of the doctrine are in Marbury v Madison(1803), which launched the Supreme Court’s power to rule on the constitutionality of legislation but also said this: ‘Questions, in their nature political or which are, by the Constitution and laws, submitted to the Executive, can never be made in this court.’
Miller (No 2), in contrast, holds that all exercises of the prerogative power are justiciable, including its highest political functions. Echoing Lord Drummond Young’s statement in Cherry that ‘any act of the executive’ is liable to judicial scrutiny, the Supreme Court states that courts have the ‘particular responsibility’ to decide whether ‘any exercise of power has transgressed [legal] limits’ (para 39). Further:‘The courts cannot shirk that responsibility merely on the ground that the question raised is political in tone or context.’
This sweeps away prior cases that were reviewed in the High Court and formed the basis for its judgment, which had approximated main features of the US doctrine. The High Court cited, for example, a joint judgment of Lord Neuberger, Lord Sumption and Lord Hodge (Shergill v Chair  AC 359) holding that an issue was non-justiciable because it was ‘political’: (1) because ‘it trespassed on the proper province of the executive, as the organ of the state charged with the conduct of foreign relations’, and (2) because of ‘lack of judicial or manageable standards’.
The Supreme Court noted receiving detailed submissions and authorities about categories of decision excluded from review because they involve ‘high policy’, but dismissed them and declined to discuss cases such as Shergill. The reason, the Court said, is that they are about the exercise of the prerogative. When it comes to the existence of a power, there are no limits of justiciability (). This distinction between the scope of a power and its exercise collapses as the Court proceeds to announce that a Prime Minister’s decision to prorogue is unlawful it ‘has the effect of frustrating or preventing, without reasonable justification, the ability of Parliament to carry out its constitutional functions as a legislature and as the body responsible for supervision of the executive’ (, emphasis added). It is impossible to determine whether this standard has been met—especially the issue of reasonable justification—without reviewing political questions of high policy involved in the exercise of power.
The lack of a judicially manageable standard is exposed in the way the Court concludes that the Prime Minister did not provide ‘any reason — let alone a good reason’ for prorogation. The Court cites John Major’s ‘unchallenged’ evidence that a government typically needs four to six days to prepare a Queen’s Speech, and claims the memorandum to the Prime Minster proposing the timetable for prorogation ‘has much to say about a new session and Queen’s Speech but nothing about why so long was needed to prepare for it’ (, emphasis added). This ignores the detailed reasons the memorandum gave for the specific beginning and ending dates of prorogation (listed in ), which were proposed on the basis of several inter-related factors independent of the sheer length of the period or the time needed to prepare the Queen’s Speech.
Perhaps the Prime Minister had a ‘bad reason’. The Inner House in Cherryconcluded that the real, unstated reason for prorogation was to prevent scrutiny of the government’s Brexit strategy and legislation that might counter it. But this required an explicitly political analysis of the Prime Minister’s motives that the Supreme Court sought to avoid. To do so would require deciding whether the Prime Minister had a ‘reasonable justification’ for prorogation and, potentially, whether certain political considerations are legitimate. Future cases will show that this is not a judicially manageable standard and that the Court was mistaken to discard limits on justiciability.
Paul Yowell is Associate Professor of Law, University of Oxford