Two months after Senate ratification of the treaty, on 22 November 1963, President Kennedy was assassinated in Dallas, Texas. The unspeakable tragedy abruptly ended any possibility of subsequent nuclear weapons agreements between himself and Khrushchev. The new president, Lyndon B. Johnson, was focused foremost on ramming through Congress the domestic reforms he advertised as the "Great Society." For continuity and simplicity he kept Kennedy's foreign policy and national security advisers in place, including Secretary of Defense McNamara.
McNamara continued to espouse a variant of the old Dulles doctrine of deterring a Soviet attack through the threat of massive retaliation, a strategic premise not wholly shared by Moscow's leaders. As the secretary of defense explained in his "posture statement" of January 1964, the United States was building a nuclear force of such superiority that it could "ensure the destruction, singly or in combination, of the Soviet Union, communist China, and the communist satellites as national societies." In addition, it could "destroy their war making capability so as to limit… damage to this country and its allies." The inconsistency of this statement is patent: there can be no need to destroy an enemy's nuclear arsenal if its entire nation has already been obliterated. But underlying what appeared to be a logical lapse was the dawning and extremely reluctant acknowledgment in Washington of the "difficulties of appreciably limiting damage to the United States and its allies." By 1964, as the strategic historian John Newhouse observed, "the recognition that the United States was in the autumn of its strategic supremacy had set in." The immediate upshot was an unresolved debate about whether nuclear missiles should be "counter-force" weapons targeted only against the Soviet Union's ICBMs and other military assets, or "counter-value" weapons targeted against major Soviet industrial centers and their populations.
A counter-force strategy was preferable for reasons of humanity if nothing else, but the possibility of a counter-value assault by a desperate nuclear power could never be altogether ruled out. The counter-value strategy enjoyed disconcertingly wide theoretical appeal. It lay firmly in the mainstream of the "strategic bombing" doctrines of the Italian theorist Guilio Douhet, who wrote approvingly in 1921, "A complete breakdown of the social structure cannot but take place in a country subjected to this kind of merciless pounding from the air." The army general William "Billy" Mitchell adapted Douhet to the American experience in the 1920s and 1930s, and in World War II the U.S. Army Air Forces had adopted these draconian concepts of annihilating the enemy and its urban-industrial infrastructure. The theories had helped to rationalize the decision to drop the first atomic bombs on Japan in 1945.
In this confused environment, both the United States and the Soviet Union began to design nuclear weapons and delivery systems that could withstand a nuclear first strike and mount a crushing retaliatory strike. The United States led in deployment of such innovative systems as hardened silos, submarine-launched ballistic missiles (SLBMs) of ever-increasing range, new generations of heavy bombers, and MIRVs (a MIRV consisted of several relatively small but highly accurate warheads atop a single ICBM, each destined for an independently preprogrammed target). Toward the end of the decade the ability to cripple the Soviet nuclear arsenal in a gargantuan strike seemed to be coming within America's reach. By 1968 the United States had deployed 1,054 ICBMs to the Soviets' 858, and the U.S. lead in the other indices of nuclear superiority was equally daunting.
Owing to this preponderance and to the enormous fiscal drain that the Vietnam War levied on defense resources, the pace of the United States buildup of strategic weapons actually began to level off at the height of the arms race in 1965. At the same time, the Soviet Union initiated a massive expansion of its strategic forces in an attempt to achieve parity with the United States. Finally conceding that the goal of limiting damage in a nuclear exchange had become unattainable, strategists in Washington began to use the term "assured destruction" in describing the standoff between the two nuclear powers. McNamara himself became convinced that neither further arms buildups nor the visionary antiballistic missile defense system (ABM) could guarantee Americans the security they craved. He began to search for a new formula for strategic stability. The answer was found in a 1946 book entitled The Absolute Weapon, in which America's preeminent strategist, Bernard Brodie, argued for nuclear equality between the United States and the Soviet Union. "Neither we nor the Russians," Brodie and his coauthors presciently wrote, "can expect to feel even reasonably safe unless an atomic attack by one were certain to unleash a devastating atomic counterattack by the other." McNamara now adopted this proposition, and it became enshrined in a telling acronym unfairly ascribed to him: MAD, for "mutual assured destruction." The converted secretary made it his mission to proselytize the American and Soviet leadership.
In 1967, U.S. leaders discovered that the Soviet Union was deploying a protective ABM system around Moscow. McNamara anxiously sought to avoid a reactionary massive increase in America's offensive nuclear forces. He persuaded President Johnson to bring up ABM defenses at the summit meeting with Soviet Prime Minister Alexei Kosygin in June 1967 at Glassboro, New Jersey. When Johnson was unable to convince Kosygin that antiballistic missile defenses would only trigger an offensive nuclear arms race, McNamara tried to explain the administration's reasoning to the prime minister. The secretary of defense described at length the action-reaction dynamic he foresaw if the Soviet Union persisted in deploying antimissile shields, and he insisted that the only way to prevent an endless arms race was to limit or even eliminate these embryonic protective systems. This reasoning infuriated Kosygin, who found the idea of abandoning defensive weapons in favor of offensive weapons to be irresponsible and immoral. His premises differed fundamentally from McNamara's. Like other Soviet leaders, Kosygin based his thinking on the cruel lessons of World War II, during which the Soviet Union suffered cataclysmic devastation at the hands of Hitler's invading armies. The imperative "never again" informed all Soviet military planning. For Kosygin, McNamara's proposal to abandon missile defenses was a direct invitation to a reprise of national disaster. Kerry Kartchner, an American disarmament negotiator, observed critically, "there is little evidence that McNamara took actual Soviet strategic thinking about nuclear weapons into account, either in determining what was required to deter Soviet leaders, or how the Soviet Union might react to American deployment of ABMs." McNamara also appeared hypocritical, because as spokesman for the Johnson administration he had testified before Congress in favor of a limited Sentinel ABM system intended to protect cities and ICBM silos from destruction in a Soviet nuclear attack.
By late 1967, McNamara's days in power were nearing their end. He and others within the Johnson administration were belatedly realizing that the parasitical war in Vietnam was unwinnable, and they soon faced incontrovertible evidence that their strategy for waging limited war had failed. The communist Vietnamese Tet offensive of January 1968 broke America's will to fight and precipitated McNamara's resignation as secretary of defense. It also induced Lyndon Johnson to withdraw from the presidential race. In November, Republican Richard M. Nixon was elected president. He inherited only one undeniably positive nuclear policy achievement from the Johnson administration: the multilateral Treaty on the Nonproliferation of Nuclear Weapons (NPT), signed by the Soviet Union and more than fifty other nations in 1968 and ratified by the United States in 1969.
The Nonproliferation Treaty set up a twotiered "regime" that divided the world into nuclear haves and have-nots. The United States, Soviet Union, France, Britain, and China were designated "nuclear weapons states" by virtue of the fact that they had tested nuclear weapons before 1968. All other parties to the treaty, officially designated as "non-nuclear weapon states," joined with the understanding that they would not seek to import or develop nuclear technology or materials for military purposes. The International Atomic Energy Agency (IAEA), which had been founded by the United Nations in 1957, was given the task of verifying treaty compliance through an elaborate inventory procedure including on-site inspections at regular intervals. The five so-called weapons states were exempt from all such controls, but they were expected to honor the regime out of self-interest. Even so, France and China were dissatisfied and did not ratify the accord until 1992.
During the treaty negotiations, India led the nonaligned states in opposing the treaty's codification of elite status for the weapons states. The principal sop that the five nuclear-armed signatories conceded to the nonnuclear weapons states was the provision to share nonweapon nuclear technology "in good faith." New Delhi strongly objected to the absence of a provision for the enforcement of this obligation. In the end, several important countries, including India, Pakistan, and Israel, refused to sign the treaty; they remained beyond negotiated global nuclear controls. Such a treaty was a thin reed of hope for nonproliferation, as Richard Nixon well knew.