Two key variables appear to have influenced the varying responses of national armies to the “Arab Spring.” The first is the manner and degree of the institutionalization of the military into authoritarian systems, and even into the few democratic or partially democratic polities, in the Middle East. No 1960s-vintage military regimes remain in the region: the various direct and indirect consequences of the oil price revolutions of the 1970s—including massive urbanization and a huge expansion of state bureaucracies and of the diversity and complexity of national economies—have seen to that. In the process, however, boundaries have blurred between the military, on the one side, and political elites, the economy, and social actors on the other. The second variable—which is partly a function of the first—is that many armies have had both inclusionary and exclusionary impacts at the same time, serving to co-opt, control, or intimidate various social sectors according to whether the latter are perceived as friendly or hostile within “threat profiles” held by state leaders, security officials, and, occasionally, wide swathes of society. The tension between inclusion and exclusion has been replicated in the social-welfare role of military employment, through which governments have shielded core constituencies from the worst impacts of deepening economic liberalization and privatization while growing numbers of their compatriots have experienced widening income disparities, declining living standards, and a descent to or below the poverty line. These trends are brought together most powerfully in the ground forces. They are not only the largest component by far of most militaries and the most affected by pressures on living standards and pensions but also the only ones that can be deployed effectively in the streets as a last resort to confront protesters. Whether armies support peaceful transition, revert to repression, or fragment will be key to their ability to maintain or develop professional, corporate identities. This ability will also be highly contingent on their readiness to accept readjustment of their institutionalization into state systems and on the manner and pace in which this is pursued by other actors. The outcome is not assured.