There are a lot of books you should read about this stuff; it'll make you more educated on it than any reply here can.
I'd start with Rousseau's 'The Social Contract,' Locke's second treatise on government, Hobbes' 'Leviathan', John Stuart Mill's 'On Utilitarianism,' Kant's Critique of Pure Reason, and Hume's Political Discourses.
I'd start with Rousseau's 'The Social Contract,' Locke's second treatise on government, Hobbes' 'Leviathan', John Stuart Mill's 'On Utilitarianism,' Kant's Critique of Pure Reason, and Hume's Political Discourses.