What gives a government the right to rule over its citizens? John Locke in his Second Treatise of Government (1689) says that government requires the real (though often implicit) consent of the people, which means it has to be in the people's interest. Unlike Hobbes, Locke thinks that the state of nature (i.e. the alternative to having a government) isn't completely chaotic and without normativity.
In the state of nature, basic laws of fairness apply (i.e. because God created us all equally, though maybe you don't strictly need that rationale to argue Locke's point), and for Locke, this includes ideas about familial rights and responsibilities (parents don't have absolute dominion over their kids but have the responsibility to guide and care for them until they're independent), land ownership (if you work the land, it's yours by right), property (you can legitimately trade things, and so, for example, collect vast hoards of gold if people around you find that stuff valuable and are willing to give it to you in exchange for things), inheritance (your property goes to those in your family you designate), and justice (each and every one of us has the right to kill those who "make war" on us, even preemptively).
All this social stuff is there for us, says Locke, before government enters the picture, so when we buy into the social contract, we're really only giving up this right to execute justice in exchange for getting an authority which can decide our disputes and act as our emissary to other governments. This doesn't give government the right over our lives (unless we break the law and "make war" on the society) or our property (though the government can tax us if it legitimately represents us), and if government officials overstep the authority given to them and act in any way against the common good, so that we as citizens would be better off not having accepted the social contract that put them in power, then they're no longer government officials, meaning we can deal with them the same way we would any private individual in the state of nature who transgresses.
We'll be trying to distinguish here between those parts of this obviously attractive to us as Americans, i.e. nobody likes tyranny, and those parts of both his argument and his resultant system that are just plain goofy.