The military reserve has traditionally been the means whereby modifications to the strength of the armed forces could be achieved at the lowest cost. With time it has become a symbol of citizenship and, for some, a way of gaining distinction. Today it is one of the elements that allow the armed forces to counter the risk (real or assumed) of isolation. Cohabitation between an operational reserve and a citizens’ reserve is probably the least bad compromise that could be found to reconcile their two mutually incompatible requirements.