Two events and two long-term developments in the late 1950s and in the 1960s forced major changes in America's alliance system. The events were the Suez crisis of 1956 and the Vietnam War; the developments were the steady relaxation of European fears of Russian aggression and the rise of mainland China as an effective world power.
The Suez crisis of 1956 found Great Britain and France, with Israel joining in for its own reasons, invading Egypt following that nation's nationalization of the Suez Canal. Ostensibly a fight to protect property, the Anglo-French action aimed at the restoration of their influence in the Middle East—influence that had begun to diminish rapidly in the face of rising Arab nationalism. Since the Middle East had not yet become a zone of confrontation between the United States and the Soviet Union, American leaders and the public viewed the Anglo-French action through their traditional prism of anticolonialism. Secretary of State Dulles publicly condemned the two European countries, and, in an ironically cooperative move, joined the Russians in applying intense pressure to force Britain and France to withdraw. Faced with such superpower unity, the two western European nations had little choice; but the diplomatic defeat at the hands of their longtime ally rankled. British conservatives had nowhere else to go, but a few years later, under the leadership of newly elected president Charles de Gaulle, the French redefined their relationship to the North Atlantic Treaty Organization. Arguing that Korea and Suez had proven that the United States cared only about its own interests and could never be counted on to defend western Europe (or anyone else), De Gaulle eventually pulled France out of virtually all the political aspects of NATO and withdrew French forces from the NATO military pool. Although the French promised to consider reintegrating their military forces if the need arose, the North Atlantic Alliance had obviously begun to deteriorate.
Still, the NATO alliance would have survived Suez and similar crises intact had the western European nations continued to fear either massive subversion or outright military attack by the Soviet Union. But those fears, at their height between 1948 and the end of the Korean War, had steadily subsided. Russian-instigated subversion seemed less likely in the wake of the remarkable economic redevelopment of western Europe, and all the members of the alliance simply assumed that the United States would retaliate with all necessary force in the unlikely event of open aggression. In short, the NATO alliance, like others, possessed a strength directly proportional to the size and immediacy of the jointly perceived threat to its members.
Another foundation of the North Atlantic Alliance, the Anglo-American entente, also changed drastically in the twenty years following the end of World War II. The outward signs of that change came in such episodes as the Skybolt missile debacle. The United States forced the British to accept an American missile system over strong protests from the British military establishment and then failed to put the system into production. But the real problem was the increasing American contempt for the deterioration of the British economy. Although Americans and the English continued to view the world through the same spectacles, the United States no longer looked for Britain to carry its share of the burden. Indeed, Britain appeared to be on the verge of economic and political collapse. Although fears of Britain's complete collapse were exaggerated, the United States refused to treat Britain as even a major partner, equal partnership having disappeared during World War II. Even the Conservative Party in the United Kingdom was thus forced to rethink its relationship with Europe. The result— and the apparent end of the Anglo-American entente—was Britain's decision, reaffirmed in 1975, to join the European Common Market. But that decision, however clear-cut it seemed in the mid-1970s, did not eliminate the Anglo-American entente. Despite De Gaulle's insistence that Britain had to choose between Europe and the United States, as the twenty-first century dawned, British policymakers still assumed that they were best suited to act as the honest broker between the United States and Europe.