The Army You Have: The Determinants of Military Mechanization, 1979-2001

Recent research suggests that a crucial factor in understanding the outcomes of military conflicts is the extent to which militaries are mechanized-that is, their relative dependence on tanks and armored vehicles compared to manpower. Since World War II, militaries have become increasingly mechanized both among the great powers and in unexpected quarters of the developing world. Yet the extent of military mechanization varies widely across states. Why have some states adopted highly mechanized force structures, while others have not? This paper tests several hypotheses about the determinants of military mechanization. One perspective suggests that strategic factors-including the force structures of adversaries and neighbors, recent combat lessons, and internal insurgency threats-shape a military's mix of manpower and vehicles. A second set of hypotheses points instead to domestic institutions such as democracy and civilian control of the military. Still other theories emphasize economic forces and international norms. To test these and other hypotheses, we construct a new data set containing mechanization rates for more than 150 militaries from 1979 to 2001. Broadly, we find significant support for the strategic perspective and little support for domestic institutional explanations. In addition, the results suggest systematic and predictable differences in the ways states structure their militaries in response to security pressures.