In 1949–1950, when western European governments feared armed insurrection, Soviet military expansion, and the power of a revived West Germany, the United States constructed the North Atlantic Treaty Organization to maintain stability, improve morale, block revolution, restrain Soviet pressure, and ease fears about the revival of West Germany. Kennan understood these purposes, but he still objected to the treaty, partly because he deemed it unnecessary. The United States would defend its vital interests (western Europe) without a treaty, he declared; there was no need to request from signatories a reciprocal pledge that they would go to the aid of the United States. A simple American pledge would suffice.
This attack on legalisms did not cut to the core of Kennan's objections. "The Russians had no idea," he later explained, "of using regular military strength against us. Why should we direct attention to an area where we were weak and they were strong?" He forecast correctly that the pact would mean "a general preoccupation with military affairs, to the detriment of economic recovery and of the necessity for seeking a peaceful solution to Europe's difficulties." In a lame effort to avoid what the Soviets might regard "as an aggressive encirclement of their country," Kennan proposed the exclusion of Greece and Turkey, and probably Italy, as outside the North Atlantic area. His criticisms found no favor with Dean Acheson, the new secretary of state.
Containment, as Kennan recognized, was taking on a life of its own. He was its uneasy sire, torn between pride and distress; he could not restrict it to the paths he wished to follow. Although popularly regarded as its preeminent philosopher and spokesman, he was being relegated within the councils of policy to the outer orbit reserved for critical scolds, for men whose judgment no longer commanded respect. Kennan and Acheson were differing on important issues involving the implementation of containment. Their differences, in important measure, were rooted in the very ambiguities of the "X" essay, especially its definition of "counterforce" and the nature of the communist threat. NATO was partly a military response to the potential insurrections that Kennan, in his unsent letter to Lippmann, had described as political, but which others labeled as military.
After the Soviet testing of their first atomic bomb in August 1949, the Truman government, which had been secretly but slowly pursuing development for some years of a thermonuclear (or hydrogen) bomb, confronted the problem of how the United States should respond to the Soviets ending the U.S. nuclear monopoly a few years before the West had predicted. Part of the Truman administration's answer was to accelerate the effort to develop the thermonuclear weapon, which could be a thousand times more powerful than the World War II A-bombs and thus could kill millions, not simply many thousands. Within the State Department, Kennan fruitlessly opposed development of this H-bomb. Reversing his 1947 positions, he pleaded, unsuccessfully, for an American doctrine of "no first use" of nuclear weapons, and decried the prospects of nuclear war. He likened nuclear war "to the concepts of warfare which were once familiar to the Asiatic hordes," and contended that use of nuclear weapons meant that "man not only can be but is his own worse and most terrible enemy."
Kennan believed that the military needs of containment could be met within the limits of the current defense budget (about $13.5 billion): the development of highly mobile, small, unified forces to deal with the likely military threats of localized, limited conflicts. In 1949–1950 his analysis conflicted sharply with that of Paul Nitze, whom Acheson would soon name as the new director of the Policy Planning Staff, for Nitze was concerned with the overall threat of Soviet arms and wanted a greatly expanded budget to provide both a limited-war capacity and, more importantly, overall strategic superiority against the Soviets.
Joined by Acheson, Nitze stressed "the Soviet purpose of world domination," and they disregarded Kennan's fears that policy should not be set down in a single document, that it would lead to distortion and a freezing of policy. In part, perhaps, Kennan had learned a lesson from the reception of the "X" essay and its hardening into dogma, albeit an ambiguous one. But more important, he believed that Nitze and Acheson were overmilitarizing American policy and misunderstanding Soviet aims. Acheson later characterized the Nitze-Kennan debate as "stultifying," for he concluded that the question of emphasis in Soviet aims—whether the Soviet Union placed world domination or survival of the regime first—made little practical difference. For Acheson, there was still a considerable "degree of risk of all-out war which the Soviet government would run in probing a weak spot for concessions."
Kennan, looking forward to the future, claimed that he was thinking of disengagement in Europe and stressed that there was no Soviet military threat to western Europe. Defeated by Acheson, Kennan watched unhappily as NSC 68, the security document embodying the Nitze-Acheson plan, moved to the president's desk. NSC 68 would cost between $38 and $50 billion, and promised, ironically, to provide the global capabilities that the Truman Doctrine had outlined, that the administration had retreated from in 1947, and that Lippmann had believed the "X" essay was promoting. NSC 68, when it was accepted after the outbreak of the Korean War, was a dramatic turning point, a bold new departure, in American foreign policy in terms of creating a larger capacity to extend and expand American commitments to stop communism.