In a dark world of French civil-military relations, the colonial army provided a shaft of light. The suspicion, the hesitation, the latent mistrust which separated republicans and soldiers at home was not transported to the colonies. Soldiers who were distrusted, spied upon and humiliated in France were pampered, promoted and decorated abroad. Overseas, the army was largely immune from close government scrutiny, free to impose its order and ideology upon the native populations which fell under its control and to carve out an area of influence which stretched from Tonkin to Timbuktu, from Pondicherry to the Palais Bourbon. The basic explanation for this lay in the nature of French colonial policy: when forced to choose either peaceful economic penetration of the unorganized world or political domination, the French chose the latter. Military expeditions became the logical corollary of French colonization, and colonial soldiers thrust into the role of conquerors were assigned the task of staking out France's colonial empire. One of the results of 130 years of colonial ramblings was the steady growth of independent habits and attitudes among colonial soldiers, which eventually rebounded on the republic with the soldiers' revolt of 1958.

The French army's modern odyssey began with the siege of Algiers in 1830. What began as a modest punitive expedition mounted for domestic political consumption, a military distraction to carry the Restoration over the difficult days of the July ordinances, in fact kicked off a campaign of conquest which was to last almost 100 years. The July Monarchy found that overseas possessions, once acquired, were difficult to let go.