The friction of terrain set up sharp, relatively inflexible limits to the
effective reach of the traditional agrarian state. Such limits were essentially
fixed, as noted earlier, by the difficulty of transporting bulk foodstuffs. Assuming
level terrain and good roads, the effective state space would have
become tenuous indeed beyond a radius of three hundred kilometers. In
one sense, the difficulty of moving grain long distances, compared with the
relative ease of human pedestrian travel, captures the essential dilemma of
Southeast Asian statecraft before the late nineteenth century. Provisioning
the state’s core population with grain ran up against the intractable limits of
distance and harvest fluctuations, while the population sequestered to plant
that grain found it all too easy to walk beyond the reach of state control. Put
another way, the friction and inefficiencies of the oxcart worked to constrict
the food supply available to the state core, whereas the relatively frictionless
movement of its subjects by foot—a movement the premodern state could not
easily prevent—threatened to deprive it of grain growers and defenders.9