Starting in the early 1960s, the nuclear taboo, which had heretofore been tentative, began to become institutionalized in arms control agreements and internalized by US leaders. The non-use of nuclear weapons in the Vietnam War helped to further reinforce the taboo and the tradition of non-use. Use of nuclear weapons there, however, in addition to being inconsistent with American political goals in the war, would also have undercut a central US foreign policy endeavor emerging in the 1960s: the renewed and more serious efforts, especially after the 1962 Cuban missile crisis, to pursue nuclear arms control and stabilize the arms race.

As noted in Chapter 3, antinuclear-weaponism had been institutionalized in the UN disarmament machinery from an early date. Now the nuclear taboo began to become institutionalized more broadly in multilateral and bilateral arms control agreements and within the US government itself. This institutionalization was often implicit (as in the 1972 Anti-ballistic Missile Treaty, discussed below), but in some cases was quite explicit (as in nuclear non-use commitments associated with nuclear-weapons-free zones). The shift toward institutionalization was made possible by widespread acceptance by US leaders of the view that nuclear weapons should be for deterrence, not use.