The origin of the term social contract can be found in the writings of Plato. However, English philosopher Thomas Hobbes expanded on the idea when he wrote Leviathan in response to the English Civil War. In this book he wrote that in the earliest days there was no government. Instead, those who were the strongest could take control and use their power at any time over others. Hobbes' theory was that the people mutually agreed to create a state, only giving it enough power to provide protection of their well-being. However, in Hobbes' theory, once the power was given to the state, the people then relinquished any right to that power. In effect, that would be the price of the protection they sought.
Jean Jacques Rousseau and John Locke each took the social contract theory one step further. Rousseau wrote The Social Contract, or Principles of Political Right in which he explained that the government is based on the idea of popular sovereignty. Thus the will of the people as a whole gives power and direction to the state. John Locke also based his political writings on the idea of the social contract. He stressed the role of the individual. He also believed that revolution was not just a right but an obligation if the state abused their given power. Obviously these ideas had a huge impact on the Founding Fathers, especially Thomas Jefferson and James Madison.