Have a look at Andrew Sullivan's Bradley Lecture on the political thought of Michael Oakeshott. A nice analysis of the ways in which Oakeshottian skepticism sits oddly with a variety fo ways of understanding conservatism.
A poltical theory dissertation ripe for the writing, it seems to me, concerns the turn to skepticism in the mid-twentieth-century liberals. The connections between Oakeshott and Hayek, and between Hayek and Popper, are fairly well-known. But Popper's skepticism has some fascinating echoes in Isaiah Berlin's; indeed, Berlin like Popper threw skeptical water onto claims of historical determinism. Shklar and Oakeshott each had Montaigne as a major point of reference. Shklar and Hayek shared Montesquieu in a similar way. (Note that, excpet for Oakeshott, each of these came from one of the European lands that spent the middle part of the century under totalitarian rule-- Berlin and Shklar from Lithuania/ Russia, Hayek and Popper from Austria.)
Now, Berlin didn't much like Hayek, and Shklar seems to have really disliked him. Berlin and Shklar were on the social-democratic side of Cold War liberalism, not on Hayek's and Oakeshott's free-market side. (Popper is a complicated case on that question.) But in all sorts of ways it seems to me that these thinkers shared insights that are more interesting than are the political questions that divided them. Yet-- except for the peculiar case of John Gray-- very few students of Hayek have also been students of Berlin. Those who know their Oakeshott don't often also know their Shklar. I have a suspicion that the study of each of these thinkers could be much enriched by the study of the others, and skepticism as part of the defense of freedom would be a major unifying theme.
Not, mind you, that the skeptical defense of freedom is clearly right. I'm inclined to think that skepticism leads us down John Gray's relativist and nihilist pathways pretty quickly. Skepticism, to be an ally of liberalism, must be something more like a temperment than like a comphrehensive theory of knowledge. Of the five philosophers, Oakeshott's skepticism ran deepest; and I can never shake the sense that Oakeshott is a philosopher of and for England only, for a country in which freedom feels organic and evolved and in little need of deliberate promotion. Each of the other four struggled with the question of how to reconcile skepticism with reform, with deliberate planned political and social change-- since one could hardly look at the world of 1935 or 1945 or 1955 and think that freedom was to be had by just leaving things alone. And I'm not sure that any of the four was fully successful in reconciling a skeptical account of the limits of knowledge and certainty and rational planning with the spirit of radical reform that liberalism required in the face of totalitatianism. Indeed-- but now I'm starting to sound like the book that I'm writing-- I think that that tension is a terribly difficult one to overcome at all points in liberalism's history. There's something importantly true in both of those liberal impulses-- the skeptical and the reformist-- but those truths sit exceedingly uneasily with each other.
But the heart of my book is in 1740-1850, not in 1930-1960; that work is for someone else to do...