Western political philosophy begins around the same time as all other philosophy. Plato (b. 429 BC) and Aristotle (b. 384 BC) wrote often about political philosophy which would, etymologically speaking, describe a philosophy of the polis or Greek city-state. Plato's ideal vision of political organization was described in his Republic, where a rule by philosopher-kings was proposed as the best form of government -- among other controversial suggestions, Plato famously spoke out against poetry and all other forms of mimetic misrepresentation, calling for their total censorship in the state. The Socratic dialogues dealing with the government of the city-state include Euthyphro, Apology, and Crito.
Aristotle tackled political philosophy in his Politics and Nichomachean Ethics and in his tutoring of the greatest politician of his day, Alexander the Great. Aristotle extended the Platonic consideration of politics taking as central questions as: What is right? How are laws justified and how should they be administered? What is the best form of government? Unlike Plato, Aristotle did not believe that there ever could be a monarch or philosopher-king of sufficient wisdom to justify monarchial rule. On the view of Aristotle, a constitutional republic would be the best form of government.
Political philosophy in the middle ages was certainly not altogether absent, but it was mostly confined to theorizing the relationship between politics and religion. In the works of Augustine (b. 354 AD) and St. Thomas Aquinas (b. 1225) most attention is given to political formations which best pave the way for Christianity.
Modern political theory probably originates with Nicolo Machiavelli (b. 1469) who was the first to (re-)consider political organization from a point of view that was not entirely religious. Of course, Machiavelli's The Prince was not concerned to demonstrate the most just form of government, it was rather a book of practical rules for rulers of Italian republics, a sort of handbook for dictators. In fact, Machiavelli wrote this pamphlet only as an attempt (a failed one) to curry favor with the Medici family, then-rules of Florence. His own political views are more fully described in the little-read Discourses on Livy, where he introduces the distinctly modern conception of the common good as being the primary purpose of government.
The Englishman Thomas Hobbes (b. 1588) is the first great writer in the tradition of classical liberalism, which can be broadly construed as the attempt to consider politics and government from the point of view of civil liberties. What was so radical about the views of Hobbes, and those who followed him, was that he undermined the notion that rule is ordained by a divine right. Hobbes and the liberal theorists conceived of rule as justified only by a contract held between ruler and ruled. Hobbes' own work must be set against the context of the English Civil War and the politlical upheavel and social instability of the period. That Hobbes advocated for obedience to a monarch is, in this context, no surprise. What differentiated Hobbes from his predecessors, and what got him into trouble, was not his view that the state should be governed by a monarch, but only that the rights of this monarch were not divine, and so the monarch was accountable to popular sentiment. Hobbes wrote that life in nature is "nasty, brutish, and short". It is the particular advantage of government that it relieves humans from their natural state, and it is this advantage that would compel both ruler and ruled to mutually enter into a political contract. Hobbes' most famous political work is his Leviathan, and his De Cive is also a work in political philosophy.
Modern political philosophy really took off in the years following Hobbes, particularly in the thought of the English philosopher John Locke (b. 1632) who, in his Second Treatise on Government in particular, further pushed Hobbes' conception of government as a contract -- Locke took the radical step of attempting to show that a populace could be justified in civil disobedience, thereby undermining the notion that law would always be equivalent to right. According to Locke, there could exist a government that would not be justified. In this case, the people would have a right to revolt. The notion of a natural right was also one of Locke's greater contributes to political rhetoric.
Like Locke, the Frenchman Jean-Jacques Rousseau (b. 1712) also undertook a sustained critique of medieval political theory, extending Hobbes' metaphor of a state of nature. Although he famously wrote that, "Man is born free, but is everywhere in chains", Rousseau believed that the bondage to our material needs in a natural state could be overcome only by a voluntary social contract. The political freedoms described in his Social Contract are best understood against the background of his theory of education described in Emile, where the best outcomes of a free society are realized in a rather bourgeoise education of the young. Other classical liberal theorists included Jeremy Bentham, John Stuart Mill, Immanuel Kant, and the American legacy represented by figures such as Thomas Jefferson and Benjamin Franklin. Contemporary theorists in the liberal tradition include John Rawls, Robert Nozick, and Ronald Dworkin.
One major extension of classical liberal logic is the political doctrines of conservatism; but it must be viewed first and foremost of an extension of the rhetorical and conceptual developments of Hobbes, Locke, and Mill rather than as a reaction against them. Classical conservatism was expounded by Edmund Burke (b. 1729) in his Reflections on the Revolution in France and is based on the twin assumptions that, a) no individual can fully comprehend the historical development and reasoning of present political institutions with sufficient ability to justify their dissolution, and b) the violence engendered by revolutions and massive social challenge will almost always be greater than the violence caused by the conservation of extant political institutions. Conservative logic underscores most popular political theory today, and if one were to chart the position of the two major American political parties both would fall under this heading, being decidely 'conservative' according to the classical models of liberal politics.
The next major upheavel in popular political thought following the development of classical liberalism would have to wait for the work of Karl Marx (b. 1818) whose breathtaking Capital is a tour-de-force rejection of the assumptions of classical liberal theory in both its political and economic instantiations (the two are ultimately, Marx argues, inseperable). With the dialectical turn in philosophy initiated by G.W.F. Hegel (b. 1770) political philosophy came to be represented historically (his classical political text is The Philosophy of Right). Rather than political theory findings its ground and justification in human rights represented by a metaphorical contract or in human happiness represented in a determinate utilitarian equation, government became in the thought of Hegel justified only by the historical unfolding of the Absolute, which each successive stage of reality would recapitulate to an increasing degree. Hegel's views are rather obtuse and difficult to understand, but if we set them within the context of the more-familiar Marxist political philosophy, we can understand the radical shift in thinking that Hegel initiated. On the views of Karl Marx and Friedrich Engels, the best form of political governance would not be a function of an objective set of rights or an objective happiness, but instead it would be a function of the material conditions of life and their ultimate viability. Material life is, of course, a thoroughly historical phenomenon (insofar as, obviously, material conditions change through time). The best form of government for a particular epoch would be determined according to the material conditions in which the people of that epoch labored. According to their famous analysis, that communism or socialism would eventually be the best form of government for the worker was a function, above all, of the material conditions of the modern world, highlighted by the unsustainable practices of capitalism.
The twentieth century has seen little in the way of original political philosophy with popular appeal. Western politics largely still work within the same conceptual frameworks developed by the Enlightenment thinkers that began the project of modern politics. That this is the case, however, does not imply that there has been little in the way of fruitful and intelligent political critique and theory in the last hundred or so years. Much contemporary political theory, in fact, offers a severe critique of the Western tradition of considering politics as a function of the Englightenment tropes of reason, human right, contract, &c. Much of the recent work in political philosophy is aimed at undermining the rhetorical tools and conceptual framework that Western philosophy has couched politics within -- what we have in many recent theorists are not so much contributions to a political philosophy, but attempts to start our political thinking over without the Englightenment baggage that is the political heritage of the West.
For example, feminism seriously questions the assumptions of a phallogocentric (or phallocentric, according to the particular theorist in question) conception of human government and the theories of desire that provide the psychological context for this conception in the first place. According to some feminist writers, political philosophy has unfairly adopted a masculine approach to political questions (and has even been overtly masculine in the very asking of the questions). Hence modern political philosophy is obsessed with the traditional appeal to reason and suppression of emotion; the traditional modeling of politics after cases of civil and international conflict (where 'rights' are supposedly contested within a context of 'justice') rather than after cases of familial or friendly conflict (where contesting emotions are at play in a single body).
Postcolonialism offers a serious challenge to the assumptions underlying classical liberalism and its extension into non-Western nations by means of imperialism and capitalism. Rather than unquestioningly accepting the concepts and contexts of Western political philosophy, postcolonialists seek to model politics after other cultural modes of formation. In this tradition, a figure like Mohandas Gandhi might be taken to be a valuable contributor to political discourse.
Anarchism, though not as academically important today as it was at the beginning of the 20th century, also offered an intelligent critique of the basic concepts in which the Enlightenment sought to discuss the notion of politics. Anarchists question the assumption that a human can live a good life according to the constricting and rule-bound concepts of modern legislative practice.
Environmentalism begins not with a consideration of human rights as foundational for political organization, but with the rights of the planets and all species as the foundation of succesful political activity.
Poststructuralist and postmodern critics of modern political institutions see in the rhetoric of classical liberalism and classical Marxism an untenable reliance on categories of thought that do not sufficiently describe the complexity of human political life. How, for instance, are we to determine a decision in cases of competing human rights? Further, what are we to do when the mere act of deciding will illegitimately inflict violence upon some party, and without good reason? According to theorists such as Jean-Francois Lyotard the basic categories according to which politics are practiced today institute a differend -- a situation in which all choices are illegitimized, thus presenting a political aporia which unsettles our very capacity for decision. It is this state of aporetic indecision that also highlights the more political texts of the French writer Jacques Derrida.
This is, of course, only an exceptionally broad and shallow survey of the field. Each of the political ideologies discussed above deserve far more attention than I could give them here. The reader is urged to read further on classical liberalism, conservatism, communism, feminism, enivornmentalism, anarchism, postmodernism and postcolonialism.