Key points are not available for this paper at this time.
A version of this paper was first presented at the London School of Economics as part of the Miliband lecture series. I would like to thank Professor David Held — a staunch supporter — for having invited me to give the lecture, the audience who turned up on what turned out to be a fine LSE occasion, the two anonymous referees for this article, and the Board of Millennium.
Michael Cox (Sat,) studied this question.