The rule according to a higher law means that no written law may be enforced by the government unless it conforms with certain unwritten, universal principles of fairness, morality, and justice.  Thus, the rule according to a higher law may serve as a practical legal criterion to qualify the instances of political or economical decision-making, when a government, even though acting in conformity with clearly defined and properly enacted legal rules, still produces results which many observers find unfair or unjust. "Higher law" can be interpreted in this context as the divine or natural law or basic legal values, established in the international law, – the choice depending on the viewpoint. But this is definitely a Law above the law.  And it is in this capacity that it possesses the equal legal value for both the common and civil law jurisdictions, as opposed to natural law which is largely associated with common law.  "To recognize the necessary connection between the rule of law as an ideal and well-constructed constitutional government does not and should not be taken to imply that all states can or should mantain the same constitutional structures in practice".
The rule according to higher law is a practical approach to the implementation of the higher law theory which creates a bridge of mutual understanding (with regard to universal legal values) between the English language doctrine of the rule of law, traditional for the countries of common law, and the originally German doctrine of Rechtsstaat, translated into other languages of continental Europe as Etat de droit (Fr.), Estado de derecho (Sp.), Stato di diritto (It.), and Правовое государство (Ru.). The latter doctrine is the product of continental European legal thought which had adopted it from German legal philosophy. Its name can be translated into English as “legal state” or "state of law" or "state of rights" or "constitutional state" – consistently meaning the state in which the exercise of governmental power is kept in check by the higher law. Amartya Sen mentioned that the legal theorists in ancient India used term of classical Sanscrit "nyaya" in the sense of not just a matter of judging institutions and rules, but of judging the societies themselves.
Before the Civil War, African Americans were legally denied equal rights and freedoms pursuant to formally valid codes prescribing the relations between master and slave. Even though these codes were de jure fully suitable for application in legal practice, yet their enforcement by the then U.S. government de facto violated basic human rights of a significant part of the population.
Generally speaking, the occurrence of such "justly enacted unjust laws" fully depends on the stance taken by the country's political leadership towards the rule of law principle.
In some countries, the political leaders assert that the rule of law is purely a procedural concept. Therefore, they argue that any government may strip its subjects of their fundamental freedoms or infringe their vital interests so long as this is done by way of a duly implemented legal mechanism. For example, at the Nuremberg trials, in an attempt to justify their crimes against Jewish and Romany population of Europe during World War II, some of the former leaders of Nazi Germany argued that they had broken none of the laws effective when Hitler had been in power. And it is only by invoking the rule according to a higher law that the Allied prosecutors were able to legitimately overcome such defenses.
In other countries, conversely, the political leaders assert that all written laws must be kept in line with the universal principles of morality, fairness, and justice. These leaders argue that, as a necessary corollary to the axiom that "no one is above the law," the rule of law requires the government to treat all persons equally under the law. However, the proclaimed right to equal treatment is susceptible to instantly becoming void each time the government denies a sufficient level of respect, dignity, and autonomy to a certain class of individuals or to human rights in general. ". Therefore, the unwritten and universally self-explanatory principles of equality, autonomy, dignity, and respect are said to overrule conventional written laws enacted by the government. It is these principles that are often referred to as "natural law." They also constitute the basis of the "higher law theory."
 Constitutional government as enforcement of the higher law
The Rechtsstaat doctrine (Legal state, State of right, Constitutional state, Constitutional government) was first introduced by the great German philosopher Immanuel Kant in his latest works completed after the U.S. and French constitutions had been adopted in the late 18th century. Kant’s approach is based on the supremacy of country’s written constitution created using principles of the Higher Law. This supremacy meant creating guarantees for the implementation of his central idea: a permanently peaceful life as a basic condition for the happiness and prosperity of the citizens. Kant was basing his doctrine exclusively on the idea of constitutionalism and constitutional government.
Kant had formulated the main problem of constitutionalism as an instrument for the practical implementation of the Higher Law as follows, “The constitution of a state is eventually based on the morals of its citizens, which, in its turn, is based on the goodness of this constitution.” This Kant’s idea has become the foundation for the constitutional theory of the 21st century. The Legal state concept is based on the ideas introduced by Immanuel Kant, for example, in his Groundwork of the Metaphysic of Morals: “The task of establishing a universal and permanent peaceful life is not only a part of theory of law within the framework of pure reason, but per se an absolute and ultimate goal. To achieve this goal, a state must become the community of a large number of people, living provided with legislative guarantees of their property rights secured by a common constitution. The supremacy of this constitution… must be derived a priori from the considerations for achievement of the absolute ideal in the most just and fair organization of people’s life under the aegis of public law.”
The Russian legal system, born in the 19th century as a result of the transformations initiated by the reforms of the Emperor Alexander II, was (and still is) based primarily upon the German legal tradition. It was from the latter that Russia had adopted the doctrine of Rechtsstaat, which literally translates as "Legal State." Its closest English analogue is "the rule of law." The Russian Legal state concept adopts the written constitution as the country's supreme law (the rule of constitution). It is a fundamental but undefined principle that appears in the very first dispositive provision of Russia’s post-Communist constitution: "The Russian Federation – Russia – constitutes a democratic federative legal state with a republican form of governance." Similarly, the very first dispositive provision of Ukraine’s Constitution declares that "Ukraine is a sovereign and independent, democratic, social, legal state." Hence, the effort to invest meaning to the "Legal State" definition is anything but theoretical.
Valery Zorkin, President of the Constitutional Court of Russia, wrote in 2003, "Becoming a legal state has long been our ultimate goal, and we have certainly made serious progress in this direction over the past several years. However, no one can say now that we have reached this destination. Such a legal state simply cannot exist without a lawful and just society. Here, as in no other sphere of our life, the state reflects the level of maturity reached by the society."
The Russian concept of Legal state has adopted many segments of constitutional economics which serves as a practical implementation of the higher law theory in economics.
Economist James M. Buchanan argues that, in the framework of constitutional government, any governmental intervention or regulation must be conditioned by the three following assumptions. First, every failure of the market economy to function smoothly and perfectly can be corrected by governmental intervention. Second, those holding political office and manning the bureaucracies are altruistic upholders of the public interest, unconcerned with their own personal economic well-being. And third, changing the government responsibilities towards more intervention and control will not profoundly and perversely affect the social and economic life.
Buchanan rejects "any organic conception of the state as superior in wisdom, to the individuals who are its members." This philosophical position is, in fact, the very subject matter of constitutional economics. A constitutional economics approach allows for a combined economic and constitutional analysis, helping to avoid a one-dimensional understanding. Buchanan, together with Kant, believes that a constitution in its capacity as the Higher Law, intended for use by at least several generations of citizens, must be able to adjust itself for pragmatic economic decisions and to balance interests of the state and society against those of individuals and their constitutional rights to personal freedom and private happiness.
Buchanan also outlines importance of protection of the moral principles underlying constitutional norms. He writes that "the ethics of constitutional citizenship is not directly comparable to ethical behavior in interaction with other persons within the constraints imposed by the rules of an existing regime. An individual may be fully responsible, in the standard ethical sense, and yet fail to meet the ethical requirement of constitutional citizenship."