340 years ago on this day, May 27th, 1679, the Habeas Corpus Act passed and became part of the laws of England. Designed to safeguard against illegal detention, it requires a detained person to be produced before court in order to ascertain if the detention is lawful. Witnesses will be required to establish this before the detention can be continued. Meaning “you have the body,” it names a person and requires the authorities to bring them before a court, thereby ruling out their ability to continue to imprison them in secrecy.

Along with Magna Carta, the Petition of Right and the Bill of Rights, habeas corpus is regarded as one of the landmarks along the road that led to the establishment of English liberties and the limits of untrammelled state power against them. These were rights that limited the power of the power of the state, then expressed in the hands of the monarch, to encroach arbitrarily on the liberties of the subject. These rights were not granted graciously by authority, nor were they natural rights deduced from something inherent in people’s nature, nor even were they derived from some ancient social contract alleged to have been made in primitive times. Instead they had evolved from the traditional ways in which tribes and societies had recognized that leaders had obligations to their fellows and followers, as well as authority over them.

Spiderman’s uncle famously said, “With great power comes great responsibility,” implying that those with power have a moral obligation to exercise its use with discretion and restraint. This is not the English tradition. It relies not on moral restraint, but on limits set by laws. Those in power are restrained, not because they are virtuous, but because they come under laws that protect every one of those subject to that power from its arbitrary use.

In Robert Bolt’s “A Man for all Seasons,” Thomas More is asked if he would give the devil himself the protection of English laws, and replies that he would.

“This country is planted thick with laws, from coast to coast, Man's laws, not God's! And if you cut them down, and you're just the man to do it, do you really think you could stand upright in the winds that would blow then? Yes, I'd give the Devil benefit of law, for my own safety's sake!”

It expresses the view that it is laws and institutions that protect our liberties, not because we choose wise and virtuous leaders, like Plato’s philosopher kings, but because we restrain them. These rights have been codified over time in acts like Habeas Corpus, but they were not established by those acts, just confirmed by them. When the Founding Fathers in America objected to arbitrary acts imposed from a distant colonial ruler, they wanted to preserve their established rights, not to seek new ones. One of their number, George Mason, stated that "We claim nothing but the liberty and privileges of Englishmen in the same degree, as if we had continued among our brethren in Great Britain.”

Habeas Corpus was an important landmark in the honourable tradition of confirming established liberties in law, and in bringing authorities under legal obligation to respect them.