La complexification des lois est une conséquence de la vie démocratique moderne qui ne cesse elle-même de devenir de plus en plus complexe. Il n’est pas possible de s’en tenir à un principe démocratique qui énoncerait la nécessité d’établir des lois simples sans prendre en compte à la fois le contexte social et la spécificité de certaines politiques. Ainsi, l’auteur expose les raisons pour lesquelles certaines législations nationales sont parfois moins complexes que d’autres en étudiant l’un des critères de la complexité législative : la densité et le degré de précision de la législation. Des institutions fragmentées par la séparation des pouvoirs ou le fédéralisme, un système politique caractérisé par des coalitions instables, un défaut de confiance du législateur envers les organes d’application, administratifs ou judiciaires, sont autant de facteurs qui favorisent des législations complexes.
Fragmented Political Structures and Fragmented Law
It is impossible to prescribe the optimal level of legal simplicity or complexity as a matter of principle, without regard to the particular policy and social context. The article demonstrates that some legal systems do enact laws that are somewhat less complex than others, and goes on to enquire why the legal complexity differs across nations, focusing on one simple but measurable aspect of legal complexity : the relative density or specificity of legislation. An institutional framework based on a strict separation of powers principle, or on federalism, weak governmental coalitions, legislative distrust towards administrative or judicial institutions, often produce legal complexity.
Fragmented Political Structures and Fragmented Law
Die wachsende Komplexität der Gesetzgebung ist eine Folge des demokratischen Lebens, das selbst zunehmend komplexer wird. Es ist nicht möglich, sich auf ein demokratisches Prinzip zu beschränken, das das Gebot der Einfachheit der Gesetze postuliert. Die Gründe der Komplexität der Gesetzgebung können je nach dem landesspezifischen Kontext unterschiedlich sein. Der Autor analysiert sie mittels eines der möglichen Kriterien : die Dichte und der Grad der Bestimmtheit der Gesetze.
Citizens and business firms in modern democratic states may feel a certain kinship with King Rex’s subjects. We now live amidst constantly growing bodies of laws that are so dense, complex, and technically-worded that we need expensive legal experts to advise us about our legal risks, rights and duties. Often even the lawyers can provide us little certainty. This growing legal complexity, according to legal scholar Peter Schuck , makes the administration of law more cumbersome, more costly, less predictable. That discourages the assertion of legitimate legal claims and defenses, especially for those who cannot afford complexity’s higher lawyering costs. “Intelligible only to experts”, Schuck warned, “the law is likely to mystify and alienate lay citizens”, diminishing their belief in the inherent justice or necessity of the law and perhaps their commitment to compliance as well .
But there is no easy escape from legal complexity. It reflects the ever-increasing complexity of modern life and of democratic politics. Hence one cannot sensibly prescribe the optimal level of legal simplicity or complexity as a matter of principle, without regard to the particular policy and social context. But as I will demonstrate today, some legal systems do enact laws that are somewhat less complex than others. Then I will explore why legal complexity differs across nations. In doing so, I will focus on one simple but measurable aspect of legal complexity – the relative density or specificity of legislation.
I. The Dilemma of Specific Rules vs. Broader Standards
Legislators all confront the issue of how detailed and specific to make the laws they enact. Some statutes include specific legal rules, such as those which prohibit driving over 60 miles per hour on roads of one kind, and limits of 30 miles per hour on others. Other statutes, however, articulate much more general standards, such as those that impose liability for accidents caused by driving “unreasonably dangerously”, or declare that family court judge’s decisions in child custody cases shall be guided by “the best interests of the child” .
The search for optimal legislative specificity is complicated, of course, by the enormous variety of human activity in populous, fast-changing societies. Even hard-working legislators, wrote H.L.A. Hart , suffer from relative ignorance of fact and indeterminacy of aim. Hence, to quote Isaac Ehrlich and Richard Posner, “the reduction of a standard to a set of [specific] rules must in practice create both overinclusion and overinclusion” .
Underinclusion creates loopholes through which clever subjects of the law can pass, subverting the legislator’s policy goals. Conversely, to be subjected to overinclusive rules is experienced as maddening and unreasonable legalism, which can prompt resistance and noncompliance . While the legislator can seek to avoid legalism by giving administrative officials, prosecutors and judges authority to make exceptions to the statutory rule when it appears unjust or unproductive to apply it literally, there is a substantial risk that different legal officials will interpret those criteria (which are general standards) inconsistently and stimulate public criticism for governmental legal inconsistency and bias. Yet steering away from the Scylla of too much legal specificity by legislating a few broad legal standards pushes the legislator toward the Charybdis of legal indeterminacy. In modern, politically-pluralistic democracies, most important pieces of legislation entail compromises among conflicting values. In practice, therefore, different implementing officials and judges may assign different weights to the blend of values in the statute, undermining legislative purpose and producing unjust decisions. 
Given these conflicting considerations, we can ask how different national legislatures vary in terms of how much implementing discretion they choose to delegate to administrative agencies and judges, that is, how much specificity to build into their statutes.
 Note de l’éditeur : cet article avait été préparé pour le colloque « Art de la Législation et Typologies des Régimes Constitutionnels » organisé à Paris par l’Institut Michel Villey pour la Culture juridique et la Philosophie du droit (24 oct. 2009)
 Fuller, Lon L., The Morality of Law, Yale University Press, 1964, p. 33-40.
 Schuck, Peter, The Limits of the Law, Boulder Co., Westview Press, 2000, p. 4.
 Ibid., p. 14-15.
 Isaac Erhlich and Richard Posner (“An Economic Analysis of Legal Rulemaking”, Journal of Legal Studies, 3 (1974), p. 257-286, p. 258) point out that more precise rules limit the number and simplicity of facts to which legal consequences attached (e.g. posted speed limit), whereas “standards” (“unreasonably dangerously”) require the consideration of numerous facts, determined and weighted according to the circumstances of the particular case.
 Hart, H.L.A., The Concept of Law, Clarendon Press, 1961, p. 125.
 Ehrlich, Isaac, Posner, Richard, “An Economic Analysis of Legal Rulemaking”, Journal of Legal Studies, 3 (1974), p. 257-286, p. 268.
 Bardach, Eugene, Kagan, Robert A., Going by the Book : The Problem of Regulatory Unreasonableness , New Brunswick, NJ, Transaction Books, 2002, ch. 4.
 For example, a 1974 U.S. Congressional Act guaranteeing public education for handicapped children said that each such child should be given “a free and appropriate education”. This general standard effectively left it to school administrators – and ultimately to the courts – to determine whether “appropriate” meant “adequate” or “optimum”, and whether the cost of the assistance needed should be taken into account. And since administrators, parents, and judges frequently have different views on those questions, and different willingness to do battle on the issue, it gradually became clear that outcomes varied from school to school, from judge to judge, and from family to family, depending, among other things, on the education level and persistence of the child’s parents.