Mulford Sibley, for many years a professor of political science at the University of Minnesota, used to frequently quote Plato's complaint in the Laws "that man never legislates but accidents of all sorts . . . legislate for us in all sorts of ways. The violence of war and the hard necessity of poverty are constantly overturning governments and changing laws." But even if most legislation is a result of accident, Mulford Sibley holds out to us the...