For US foreign policy, the Stockholm conference represented a significant stage, which American diplomacy reached after months of specific, intense work. In particular, the convergence of the environmental interest shown by the Nixon Administration with the international path sponsored by the United Nations since the end of the 1960s produced on this occasion direct effects on the definition of an adequate US environmental diplomacy, which so far had been rhapsodic and occasional. By virtue of an increase in the number and professionalization of officials, but also the creation of ad hoc bodies, the action now planned at the Department of State was able to carry out a wide-ranging activity with defined objectives, which centered on the UN General Assembly but in a coordinated manner with other multilateral fora. Along with the political needs imposed by the Cold War, it was an action that had to be constantly homogenized with the strategic posture related to the Soviet Union, but not only: the path to Stockholm is also rich in correlations with development issues and the new actors which embodied their claims, the Vietnamese and Chinese variables, the echoes of an in-depth internal debate: this essay aims to retrace in a unified manner various inspiring motives of the American conduct, based on a historical-diplomatic perspective.