The social contract principle was introduced during the Enlightment era by Jean Jacques Rousseau and John Locke and states that the power of a state resides on its citizens who can grant it to political representatives elected through suffrage and would propose and implement policies on their behalf. This is the base of modern representative democracies that can be found in the most advanced countries such as the US or in European countries.
The principle of the division of powers was introduced by Montesquieu during the Enlightment era and states that the power of a state has to be divided in three independent branches: legislative, executive and judiciary. Moreover, a system needs to be develop to ensure that none of the branches gathers enough powers as to overrule the others. For examples, the three branches are controlled and balanced in the US, through the so-called System of Checks and Balance.
The establishment of individual freedoms and civil rights, which nations started to approach during the Enlightment era with the enactment of Bills of Rights, is still basic in current democracies These guarantee rights to its citizens such as freedom of speech, freedom of assembly, right to trial, equal voting rights, etc.
