Introduction
Central to the idea of the rule of law is the requirement that even governments must be bound by law.1 Under the rule of law, even those who have the ability to make and change the law remain subject to it. Even those who have the power to interpret and enforce the law remain governed by it. It is this feature of law, as much as the ballot box or the free press, that protects the ordinary citizen from arbitrary state power.2
Understood in this way, the rule of law is more than just the requirement that governments must act according to the law. Should a law be passed that gave a government the power to act whenever and however it wanted, such a government would not be bound by law. To be genuine, rule of law must place substantial, non-trivial constraints on the use of state power, just as it does with ordinary citizens. It requires not only that government authority be exercised in accordance with publicly disclosed and appropriately adopted procedures.3 It also requires that genuine prohibitions exist against at least some types of state action. It is in this sense that rule of law differs from rule by law or rule through law.
Simply put, rule of law requires not just that all government actions find their source in law. It also requires governments to acknowledge the difference between powers granted to them in law and powers they do not have.
In 2006 in Hamdan v. Rumsfeld, the US Supreme Court struck down the use of military commissions established for the purpose of trying suspected terrorists at the US Navy base in Guantanamo Bay, Cuba. It was the court’s conclusion that without congressional authorization the government of the day lacked the authority to initiate such trials. Even though Mr. Hamdan had confessed to working closely with Osama bin Laden, the court ruled that, “in undertaking to try Hamdan and subject him to criminal punishment, the Executive is bound to comply with the Rule of Law that prevails in this jurisdiction” (p. 72). In other words, no administration has the power to act in such cases unless it has the legal authorization to do so. This same observation was made two years earlier in Hamdi v. Rumsfeld. There, the court put the point even more bluntly: “We have long since made clear that a state of war is not a blank check for the President” (p. 29).
Nothing in these two decisions is new. In London in 1762, the King’s Chief Messenger, a Mr. Nathan Carrington, broke into the home of the writer John Entick looking for proof of sedition. The resulting trial, Entick v. Carrington, focused on whether Carrington, as an agent of the Crown, had unlimited powers or whether his only powers, qua government agent, were those granted to him in law. The court’s decision was clear: Carrington had no powers over and above those assigned to him in law. The case served as motivation for adoption of the Fourth Amendment in the United States in 1792. It also gave rise to the famous dictum, “If it is law, it will be found in our books. If it is not to be found there, it is not law.”4
The Entick decision has influenced western democracy’s view of government ever since. When the question of Quebec separatism arose in Canada in 1998, Canada’s highest court concluded in its Reference re Secession of Quebec that any actions leading to the possible breakup of the country would have to take place according to the law. As the Court reminded Canadians, even though “democratic institutions necessarily accommodate a continuous process of discussion and evolution, which is reflected in the constitutional right of each participant in the federation to initiate constitutional change” (p. 150), and even if there were to be a clear referendum result requesting separation, no province could purport “to invoke a right of self-determination to dictate the terms of a proposed secession to the other parties to the federation” (p. 151).5 Even in such dramatic circumstances, it is the rule of law that establishes how and when government action may be undertaken. It is the rule of law that gives government its power, both modest and far-reaching, and, by placing limits on this power, it is the rule of law that “provides a shield for individuals from arbitrary state action” (p. 70). Even acts of secession and other acts intended to rewrite a country’s most fundamental constitutional law must proceed in accordance with the law. No act of government, let alone an act of separation, can be carried out unless it is authorized through procedures recognized in law.
Admittedly, throughout history there has been no precise, universally agreed-upon definition of the rule of law.6 Some commentators have held that the rule of law is something purely formal, requiring only that laws be publicly and unambiguously promulgated after being created by those who have the proper authority to do so.7 Others have held that the rule of law is something more substantive, requiring that specific social, economic or political conditions be met, for example, that certain legal rights or economic goods be guaranteed.8 Others have held that the rule of law must be related to theories of natural law, to theories associating law with various normative concepts justified through reason.9 Yet others have understood the rule of law as having a necessary connection to democracy.10
Despite these various suggestions, there remains widespread agreement in today’s courts that, unlike rule through law, rule of law exists most clearly in contrast to rule by arbitrary power. As much as anything, it is this idea—that no government is all powerful, that even governments having the authority to create and enforce the law must be bound by it—that distinguishes modern constitutional democracy from other forms of government, including theocracy, totalitarianism and unrestrained mob rule.
The Arginusae Trial
How did this idea—the idea that even governments must be bound by the law—first arise? How did we come to believe that even the most politically powerful among us are not all powerful? Like so many ideas central to the democratic ideal, it originated in ancient Greece. In a trial that today often remains overlooked, it was one man’s dedication to the law that helped establish the first rudimentary distinctions between constitutional democracy and mob rule.
In 399 bce, the philosopher Socrates was charged with believing in false gods and corrupting the young.11 He was found guilty and sentenced to death.12 To carry out the execution he was required to drink a cup of hemlock, a type of poison. Plato tells us he did so without hesitation (Phaedo, 117c), believing he had a duty to follow the law even when it happened to go against his interests (Crito, 45c–54e).
What is less often remembered is that seven years earlier, in 406 bce, Socrates was involved in another important trial, one that in its day was even more famous than the trial that eventually led to his execution. This earlier trial, referred to by historians as the Arginusae trial, deserves to be remembered, not simply as a contributing factor to Socrates’ guilty verdict, but as a crucial step in the development of what we now call the rule of law.
As in other Athenian trials, the epistatês (or presiding officer) in the Arginusae trial was chosen by lot. Plato and Xenophon both report that, as luck would have it, it was Socrates who was chosen to fill this important role.13 It was during this trial, in the most dramatic of circumstances, that Socrates publicly insisted that even Athenian lawmakers must be bound by the law.
Just as modern law on occasion allows for impeachment and trial within some legislative bodies, Athenian law sometimes made it legal to try people in the Assembly.14 The process was reserved for important, powerful people. It is reported that as well as being used in the Arginusae trial, the process was used on only ten other occasions.15
Within ancient Athens, it was ordinary adult, male citizens who exercised most of the city’s political power. Of course, some men were appointed to serve as government officials, but for the most part, they were selected by lot and served relatively short terms.16 A few officials, like generals (stratēgoi), were elected. Even the democratic Athenians refused to serve in military campaigns led by leaders chosen by lot. Despite such exceptions, the great majority of important decisions were made not by elected or appointed officials, but by the people (demos) themselves in their regular meetings of the Assembly.
Overseeing the Assembly (or ekklēsia) was an administrative body called the Council of 500 (or boule). This body had considerable but limited power. It set the Assembly’s age...
