The constitutional foundations of reasonableness review: artificial reason and wrongful discrimination

Judicial review of the executive faces a constant threat of constitutional illegitimacy. Historically, this manifested in a conflict between the common law and the royal prerogative, with the judiciary needing to justify its authority to set legal limits on the powers of a divinely authorised monarch. This conflict has now transformed into a clash of political and legal conceptions of democratic governance: executive discretion to decide upon and efficiently pursue the common good conflicting with judicial enforcement of foundational constitutional norms designed to ensure that this pursuit is lawful. This paper will look to the founding of the law of judicial review and the writings of Sir Edward Coke to illuminate some of the dark corners of the modern law of reasonableness review. Coke's theory of the common law as a body of artificial reason will serve to place reasonableness review within its appropriate constitutional context, solidifying the connection between the rule of law and non-arbitrariness by elucidating the foundational role that constitutional principle plays in identifying unreasonable executive conduct. Once this is done, it will become clear that the value of legal equality, manifesting in a principle of non-discrimination, is vital to reasonableness review.