The New Constitution: U.K. Supreme Court Intervenes In Brexit Debate

Byron Shaw is a litigation partner and the co-author of Constitutional Law with Justice Patrick Monahan and Padraic Ryan.

Awi Sinha is a litigation partner specializing in Government Law & Political Risk.

Emily Leduc-Gagne is an articling student at McCarthy Tétrault.

Law, Not Politics?

The U.K. Supreme Court entered the explosive Brexit debate yesterday, ruling that Prime Minister Boris Johnson's advice to the Queen to prorogue Parliament until October 14th was unlawful. In a unanimous 11-judge decision written by Lady Hale and Lord Reed, the Court in R (on the application of Miller) v The Prime Minister, [2019] UKSC 41 held that Johnson exceeded the limits of the prerogative power. The Court expressly stated that its decision was a straightforward application of legal principles. Lady Hale and Lord Reid held that courts can and do rule on the extent of executive powers[1]; here, the Court was ostensibly defining the limits of the prorogation power, which were exceeded in this exceptional case.

According to the Court, "a decision to prorogue Parliament (or to advise the monarch to prorogue Parliament) will be unlawful if the prorogation 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 the supervision of the executive. In such a situation, the court will intervene if the effect is sufficiently serious to justify such an exceptional course[2]."

The Supreme Court therefore held that the government has a positive obligation to provide a reasonable justification to prorogue, failing which, its advice (and, by extension, the Queen's decision based on that advice) is null and void[3].

In other words: this is law, not politics. Is it?

Politics, Not Law

The Court's ruling is unquestionably political in terms of the subject matter of the decision. It requires that British MPs return to Parliament and continue working in the run-up to the Brexit deadline of October 31, 2019 notwithstanding the existing government's publicly declared support for a "no deal" Brexit.

The decision is also political in the sense that it arguably expands the role of the judiciary into what has previously been an area in which the Courts have treaded delicately. The Court's ruling is difficult to reconcile with Britain's traditions of Parliamentary supremacy and the role of the judiciary in a country with no written constitution.

The Court presented the decision as simply defining the limits of executive power, something entrusted to the courts in a constitutional democracy. It took great pains to state that it was not reviewing the "mode of exercise" of the Johnson government's decision to prorogue or its "motives"[4]. On closer examination, that is exactly what the Court did.

The...