In the Declaration Of Independence, this refers to yet another one of the famous John Locke's ideas known as 'Social Contract'
Social Contract is the idea that citizens give a government its power and have the authority to take away that power -- In turn, the government promises to protect the people and their Natural Rights.
Social Contract was created in order to stop a government from misusing its power. If a government was to misuse its power, social contract stated that the people/citizens could replace or overthrow the offensing government.