In common-law legal orders, public power is supposed to be exercised in accordance with the rule of law. Administrative law, the law that governs the exercise of power by public officials, is the body of rules and principles developed by judges to ensure that when public officials act, they act in accordance with the rule of law. Severe tensions can arise within the common-law understanding of administrative law when a legislature enacts a law that meets the legal order's formal criteria for validity, yet purports to exempt officials from the requirements of the rule of law. If those officials' decisions are challenged before a court, should the court declare them invalid simply on the basis that they fail to accord with the rule of law? Judges who adopt positivistic theories of law will generally answer "no" to this question, while judges of a more natural law bent will tend to answer "yes." The former will determine a law's validity based only on the criteria explicitly set out in the positive law of their order, while the latter will think that there is more to the question than positive law--namely, the transcendent moral values of the rule of law.
Although judges of a natural-law bent will likely appreciate the tensions better than positivistically inclined judges, a more sophisticated response to the problem is available than one that simply reduces it to a question of whether a law offensive to the rule of law is or is not a law. That response presupposes a natural-law understanding of the rule of law, one which holds that the value content of the rule of law transcends what any formal source of law declares the law to be. However, such a response does not require that a law is always invalid when it fails to comply with the values of the rule of law. Rather, all it requires is that the tensions created by such a law are understood as tensions internal to legal order, tensions which must be resolved in order for that legal order to sustain its claim to be such--an order constituted by law. Thus, judges are not necessarily always able or even often best suited to resolve such tensions.
An exploration of this response begins with an account of how judges in common-law legal orders have found the norms of international law, in particular international human rights law, helpful in elaborating their understanding of their role in upholding the rule of law. Indeed, international human rights law has helped greatly to clarify the idea of the rule of law on which the judges rely, both in terms of the interactions among its components and the assumptions that hold it together. Judges have found international law particularly useful in ensuring that the rule of law is respected in an area in which traditionally positivistic judges have deemed the rule of law inapplicable--namely, in the exercise of public power, which is based, not on law, but on the prerogative of the executive to deal with immigration and national security as it sees fit. Natural-law judges have been amenable to the influence of international law because their understanding of law and the rule of law rejects positivistic assumptions that lead to the marginalization of international law, even to its very claim to be law. However, international legal bodies have proven capable of introducing the same sorts of tensions--tensions often created in the areas of national security and immigration.
One might say that these natural law judges, working within the common law tradition, have paid international law the compliment of not only recognizing its claim to be law, but also of considering it to be constitutive of their understanding of the rule of law or legality, so that public officials must comply with international law if they are to abide by the rule of law. Thus, it is incumbent on the international bodies charged with making decisions affecting the interests of individuals subject to their legal regimes to repay the compliment. …