The emergence and development of detente between the United States and the Soviet Union after the Cuban missile crisis of October 1962 reflected a mutual desire to move away from the dangerous confrontational policies of the cold war. A mutual desire to move in the direction of detente had been powerfully stimulated by the brush with thermonuclear disaster during the Cuban missile crisis in 1962. The Basic Principles Agreement included much more than a vague commitment to crisis prevention. It was described by US and Soviet leaders as a sort of charter for detente. Policy legitimacy for detente was necessary in the Soviet Union but the problem of domestic constraints on the conduct of a long-range foreign policy of this kind arises in a less acute form in a nondemocratic political system. Richard M. Nixon and Henry Kissinger were acutely aware of the dimensions of the challenge they faced in obtaining and maintaining sufficient domestic support for their detente policy.