"Journal of Moral Philosophy" (vol. 10, issue 3, 2013) features an article by Charles Larmore:
"What Is Political Philosophy?" [pdf]
"What is political philosophy’s relation to moral philosophy? Does it simply form part of moral philosophy, focusing on the proper application of certain moral truths to political reality? Or must it instead form a more autonomous discipline, drawing its bearings from the specifically political problem of determining the bounds of legitimate coercion? In this essay I work out an answer to these questions by examining both some of the classical views on the nature of political philosophy and, more particularly, some recently published writings by Bernard Williams and G.A. Cohen."
Charles Larmore is Professor of Philosophy at Brown University. He is the author of "The Morals of Modernity" (Cambridge University Press, 1996) and "The Autonomy of Morality" (Cambridge University Press, 2008).