Final answer:
King John was forced by the English nobles to sign the Magna Carta due to his unpopular fiscal policies and abuses of power. The document limited the monarchy, enshrined due process, and influenced future legal systems.
Step-by-step explanation:
The nobles forced King John to sign the Magna Carta in 1215 primarily because they were unhappy with his heavy taxation and arbitrary exercises of power. His attempts to finance military campaigns and regain lost territories had led to the imposition of excessive taxes and the exploitation of feudal privileges. Frustrations over these actions, particularly the loss of Normandy, compelled the nobility to press for a formal document that would limit the monarchy's power and ensure legal rights for the nobles. The Magna Carta established the principle of due process, which meant that a free man could not be penalized unless given a lawful judgment by his peers. This charter laid the groundwork for a clearer legal system in England and influenced many modern legal systems, including that of the United States.
Moreover, the Magna Carta laid the foundation for constitutional governance by establishing the idea that even the monarch was subject to the rule of law. It introduced the concept that the king's power should be tempered by legal constraints and that certain legal procedures must be followed before imposing penalties. This seminal document, while initially focused on the concerns of the nobility, contributed to the broader development of individual liberties and legal protections. The Magna Carta's legacy reverberated through history, influencing constitutional and legal frameworks worldwide, including the U.S. Constitution and the concept of a fair and impartial legal system that remains integral to modern democracies.