What turned precariously poised relationships into unsustainable ones were crises impacting several empires at the same time, crises whose course and outcome no one metropole could control.

Since the mid-eighteenth century four wars were fought to determine which states would dominate world affairs: the Seven Years’ War (1756- 63), the Napoleonic Wars (intermittently between 1799 and 1815), and World Wars I (1914-18) and II (1939-45).

Each struggle for global hegemony had distinctive, unique features. Are there any broadly similar patterns in the conduct and aftermath of these four wars? If so, the parallels may account for shared postwar outcomes of imperial decline.

Phases 2 and 5 were each preceded by a war that stimulated formation of a colonial protest movement, though protest was not initially manifested as a drive for independence. These preparatory wars set the stage for follow-up struggles which engaged many movements aiming explicitly at sovereignty. The Seven Years’ War had a catalytic—albeit indirect and delayed—effect on the independence movement in bna. Its impact was similar in many ways to World War I’s effect on the inc in India. The Napoleonic Wars and World War II can be seen as follow-up conflicts. Each built on changes introduced by the war preceding it. Each had a more direct, immediate, and wide-ranging impact on decolonization than its predecessor. The implication is that it took not one hegemonic war but two to undermine overseas empires. The cumulative repercussions of the Seven Years’ and Napoleonic wars ended European dominance in most New World mainland settler colonies.

In another recurring pattern, major contestants in hegemonic wars selectively supported movements for independence from other metropoles. In some cases sup­port was tendered during wartime, as when British diplomats early in World War I offered to assist Arabs in throwing off Ottoman rule. Declarations of American sup­port for the principle of national self-determination—somewhat qualified in Presi­dent Wilson’s Fourteen Points, unequivocal in the Atlantic Charter—were widely welcomed by nationalists. In other cases assistance was extended after a war was over. Examples are French military intervention on behalf of American revolutionaries— in effect repaying England for France’s defeat in 1763—the thousands of British volunteers in Spanish American liberation struggles, and British Foreign Secretary George Canning’s threat of naval intervention to prevent Spain from trying to recon­quer its former colonies. In these situations interstate competition helped dissolve empires, whereas in other situations examined in chapter 9 it was a force driving imperial construction.

Victory in war often precipitated imperial decline. This outcome is less para­doxical than might appear. Metropoles proud of having triumphed on the world scene felt entitled to assert authority in their own domains. They also wanted to extract resources to pay for the war, whose costs were reflected in heavy postwar debt burdens. In asserting control over affairs they in effect turned the clock back to prewar days. Their reactionary policies in turn generated immediate, intense opposi­tion from colonial elites. The primary triggers of independence movements were not wartime crises at moments when metropoles were unusually weak, but postwar crises at moments when metropoles wanted to be seen as unusually strong. Pressures for independence intensified when metropolitans balked at reform and insisted on remaining dominant.

This is not to deny that defeat contributed to imperial decline. An empire losing a major war cannot avoid confronting internal shocks and external pressures sufficient to break it up. This occurred after World War I with two land-based empires, Austro-Hungarian and Ottoman. When European states lost to one another their possessions frequently changed hands, as in the wars of phases 1 and 2 and in modified form in phase 4 when Germany’s possessions passed to the victors via League of Nations mandates. Temporary loss of Southeast Asian colonies to Japan clearly accelerated the demise of European rule there. Still, what is striking is that victory in struggles for global hegemony not only failed to guarantee dominance within the victor’s overseas domains but actually undermined it.

Another recurring problem is that independence movements in phases 2 and 5 went through similar sequences of change. The most immediate effect of war was on the capacity of metropoles to control colonies and of colonies to assert autonomy. In many instances wars lowered the former and raised the latter. In contrast, postwar crises were primarily conflicts of will. As these crises unfolded, each side displayed increased resolve to resist the claims of the other. Willingness to compromise dis­solved at a time when the capacity gap between imperial center and periphery was smaller than ever before.

The following sequence can be observed in diverse times and places: During wartime a metropole experienced loss of control over a colony. Needing to defeat its enemy, it called on the colony for assistance. Colonial elites were prepared to help if they could be assured that the colony would be at least as well off politically after the war as before, and hopefully in a better position to chart its future. Colonial elites did their part, thinking that such a bargain had been struck. But once the war was won the metropole no longer needed help to survive.

In broad terms, this sequence proceeded from reduced metropolitan capacity to increased metropolitan will to increased colonial will to increased colonial capac­ity. The components of power changed for both sides. But they did so in a pattern that gave a colony greater leverage in the postwar setting than before the war because both components of its power were on the rise. Metropolitan will rose to compensate for loss of capacity. Colonial capacity to organize for independence rose in response to rising will, the two components synergistically reinforcing each other.