It failed mainly because it was based on flawed assumptions and false premises, the foremost of which was that the Soviet Union wanted strategic arms limitation agreement much more than the United States did.[173]
Seeking to foster better relations with the United States, China and the Soviet Union both cut back on their diplomatic support for North Vietnam and advised Hanoi to come to terms militarily.[174] Nixon later described his strategy:

I had long believed that an indispensable element of any successful peace initiative in Vietnam was to enlist, if possible, the help of the Soviets and the Chinese. Though rapprochement with China and détente with the Soviet Union were ends in themselves, I also considered them possible means to hasten the end of the war. At worst, Hanoi was bound to feel less confident if Washington was dealing with Moscow and Beijing. At best, if the two major Communist powers decided that they had bigger fish to fry, Hanoi would be pressured into negotiating a settlement we could accept.