Yes, everyone has heard of the Great Charter King John of England signed. It is considered a foundational document in English and American law.
It was, in fact, a political football and an utter failure.
King John and his barons were feuding, the barons threatening rebellion and John threatening dire retribution. They were of course negotiating, but like politicians of any age, they were also covering their bases. John was talking to the Pope to back him in punishing the barons and the barons were eyeing French Prince Louis as their new sovereign. Both sides were making preparations for war.
Into this powder keg situation comes the Great Charter, setting out reforms in English government meant to make several particular barons happy, and generally limit the arbitrary, absolute nature of royal rule for all the barons.
“Please Lord King, we must address these abuses,” said the barons.
“Certainly” replied King John “No king wants to abuse his subjects”.
Fact is everyone involved had one hand on their daggers the whole time.
The charter’s effectiveness can be measured by the fact that England’s First Barons’ War took place soon after it was sealed.
So why is Magna Carta so revered now?
Because it served as a template. It was reissued by the regents ruling in the name of John’s son Henry III, with the clauses most despised by the royal government removed, to serve as a weapon against the rebellious barons. It was reissued several more times, until the 1225 edition, which became the Magna Carta that did formally enshrine in English law the notion that people had certain rights that no government could override. Inalienable rights, as the phrase goes. These include lawful judgment by peers using credible witnesses, that punishments should match crimes, and that property should not be arbitrarily seized.
To be sure there were and still are abuses of the law, but Magna Carta laid out the formal principle that government should do Right, not simply serve Might. And that notion is always needing expression.