For a quarter century the slow but continuing trend in NATO strategy—and in thinking about NATO strategy—has been from emphasis on nuclear deterrence to emphasis on conventional deterrence. When it became clear that the famous Lisbon force goals of 1952, embodied in MC 14/1, had no hope of realization, NATO strategy appropriately stressed the deterrent role of nuclear 16weapons, in terms of both massive retaliation by US strategic forces and the early use of tactical nuclear weapons in Western Europe. This strategy was codified in MC 14/2 in 1957. Shortly thereafter, however, the development of Soviet strategic nuclear capabilities and, more particularly, the massive deployment by the Soviets of theater nuclear weapons raised serious questions as to the desirability of NATO's relying overwhelmingly on early use of nuclear weapons to deter Soviet attack. In the following years, the emphasis shifted to the need for stronger conventional forces capable of mounting a forward defense of Germany for a period of time and to a strategy of flexible response, in which, if deterrence failed and if conventional defenses did not hold, NATO would have the options of resorting to tactical, theater, and eventually strategic nuclear weapons. In 1967 this strategy became official NATO policy in MC 14/3.