civilian population centers. This proposal represented an American attempt to draw a distinction between “countervalue” attacks, which would strike a full range of social and political targets such as cities and government institutions, and “counterforce” attacks, which would be aimed only at military assets. The goal, at least in theory, was to enhance crisis stability by showing a willingness to discriminate between military targets and cities; presumably, an enemy would be more willing to tough it out and not attack during a tense period if assured that the other side had not targeted civilians and urban centers. At the least, an offer to limit targets might spur a similar pledge from the opponent and keep a nuclear exchange from raging out of control. Ideally, it would help avert war itself not only by sending a message of restraint to the Soviets, but by showing that the United States had come up with a real purpose for nuclear weapons besides the mindless killing of Soviet citizens.20
“No cities” was one of many attempts to place a rung on Kahn’s ladder somewhere between the outbreak of conventional hostilities and total nuclear war. Like Massive Retaliation, however, it was inherently flawed. Indeed, it was a strategy that only a pure theorist could love, and it could not survive first contact with the real world, where its success would have to rely on the goodwill of a cooperative adversary in the midst of a possible holocaust. Even if both belligerents could reach some sort of prior agreement about conducting a nuclear war, a strategy of “city-avoidance” was doomed from the start by the fact that so many Soviet targets, and no small number of American assets, were located close to population centers. Were Moscow and Washington, the military nerve centers of their respective nations, to be spared? (And if they were slated to be destroyed, who would be left to negotiate a ceasefire or surrender on either side?) The sanctity of cities could never be guaranteed, and a promise not to hit them, or at least not to hit them in the first thirty minutes of the war, was not a promise worth making.
After a period of vigorous debate in the 1960s (during which the shock of the 1962 Cuban missile crisis nearly rendered the whole Soviet-American conflict moot), the United States and its allies in 1967 codified a strategy of “Flexible Response,” which NATO described as “a flexible and balanced range of appropriate responses, conventional and nuclear, to all levels of aggression or threats of aggression” (emphasis added).21 Here, the Americans and their allies tried to overcome the credibility problems inherent in “extended deterrence,” and to link the defense of North America to the defense of the entire North Atlantic community. Rather than threaten discretionary retaliation at “times and places of our choosing” with the consequent killing of millions of civilians on both sides, U.S. and NATO strategists instead crafted a strategy of deliberate escalation backed by a wider menu of both conventional and nuclear military choices. Now, NATO would fight its way up the escalatory ladder, instead of jumping from the first rung to the last.
As before, the conventional defense of NATO in Europe had virtually no chance of succeeding against a Soviet invasion. That, of course, was the point: the United States and its allies might not resort to strategic nuclear attacks at the outset of the war, but if faced with a Soviet onslaught, they would have no choice but to escalate to tactical nuclear options on the battlefield. The first salvos would halt the Soviet advance, and then the burden either of defeat or escalation would shift to Moscow. Instead of the bluster of Massive Retaliation, the new approach in Flexible Response tried to convince the Soviets that escalation would happen practically by default. Nuclear use would no longer have to result from courageous or stoic American decisions, but would instead be driven by Soviet actions.
Flexible response relied on presenting the Kremlin with a paradox, in which the success of Warsaw Pact conventional forces on the battlefield would increase the chance that nuclear weapons would be used against them. Accordingly, U.S. nuclear weapons were intentionally placed in forward positions where they would be overrun by advancing Eastern forces. Henceforth, the Soviets would know that if war broke out in Europe, NATO commanders would be cornered, through no fault of their own, into having to use their nuclear arms or lose them once overwhelmed. Soviet leaders, at least in theory, would be presented with a storyline they could understand and believe, in which the first Soviet bullet fired in Europe would inexorably be tied to the last U.S. or British missile launched from the last silo or submarine. The Soviets would therefore understand that war would likely lead to consequences that neither side wanted but that neither could escape if a crisis were to spin out of control.
NATO’s explicit rejection of “no first use,” the pledge not to initiate the release of nuclear weapons, was central to this strategy. Logically, a promise not to escalate to nuclear force had to be rejected as a matter of doctrinal first principles: if the Soviet Union truly intended to menace Europe, NATO thinkers reasoned, a “no first use” pledge would be an open invitation to Moscow to try to keep the conflict at the conventional level, where the Soviet advantage was greatest. Instead, NATO’s adoption of Flexible Response hammered home the point that the Americans and their allies were ready to drag the Soviets, rung by rung, up the escalatory ladder. A conventional war risked a battlefield nuclear war, and the tactical use of nuclear weapons risked theater nuclear war. At that point, the sunk costs of millions dead, the imminence of defeat, the panic of mass destruction, and the fog of war would all combine to make general nuclear war seem plausible and perhaps even probable. With Flexible Response, NATO was hoping to convince the leaders of the Kremlin that no matter how many men in the Red Army or missiles in the silos of the Strategic Rocket Forces, a war in Europe could not be won and to embark on such a mad enterprise would gain nothing while risking everything.
Parity and the Advent of Mutual Assured Destruction
In the mid-1960s, the Soviets began a major military buildup, including rapid increases in their nuclear forces.22 By the end of the decade, the USSR would catch up to the Americans in strategic nuclear power, creating a situation of approximate nuclear equality, or “parity.” While somewhat unequal in the numbers and distribution of their forces, by any standard each side now controlled roughly as much nuclear firepower as the other, and each could surely destroy the other under any circumstances. (Later in the decade, American secretaries of defense James Schlesinger and Harold Brown would use other terms such as “essential equivalence,” but the idea was the same.) The mathematics of parity were unarguable, but the politics were less clear: what did it mean now that East and West were so closely matched?
In concrete terms, little had changed since the early 1960s. Nuclear war still meant appalling levels of damage to both sides, with no hope of anything like a meaningful “victory” for either East or West when it was over. The arrival of Soviet-American parity represented the crossing of a psychological borderline more than a change in the military balance, since it was achieved at numbers of weapons so high that any asymmetries were functionally meaningless. For many American strategists, parity meant the end of any further toying with the pretense of fighting, much less “winning,” a nuclear war.
In fact, McNamara and his deputies in President Lyndon Johnson’s administration had already decided by the late 1960s to take what they saw as a more direct and stabilizing approach, and to discard the question of victory entirely. Instead, the Americans sought to stress to the Soviets the unavoidable and permanent damage that both sides could do to each other. The Americans proposed, in effect, to enter into a mutual hostage arrangement with the Soviet Union, where each side would forego defenses, cap limits on strategic arms, and do their best to avoid all-out nuclear war. Any indication that either side felt it could survive a nuclear war, such as civil defense programs, would be considered provocative. Likewise, there would be no attempts to hide the size and readiness of retaliatory forces. The more each side understood about the reliability of the other’s deterrent, the better. The Americans hoped that the Soviets would internalize and institutionalize the central fact of the superpower confrontations in the 1950s and 1960s that culminated in the Cuban scare: every crisis carried the risk of the extinction of both combatants.
The Soviets were not persuaded, or at least pretended they were not persuaded. The flinty Soviet marshals conceded only that victory, at best, would be defined not
