The central principles of what today is broadly-known as political liberalism were made current in large part by Locke's "Second Treatise of Government" (1690). The principles of individual liberty, the rule of law, government by consent of the people, and the right to private property are taken for granted as fundamental to the human condition now. Most liberal theorists writing today look back to Locke as the source of their ideas. Some maintain that religious fundamentalism, 'post-modernism', and socialism are today the only remaining ideological threats to liberalism.