Common knowledge has it that the end of the Cold War allowed the North Atlantic Treaty Organization (NATO) to push the nuclear genie back into the bottle. But whilst NATO members have reduced the alliance’s practical, military reliance on nuclear arms, their commitment to nuclear defence as a shared, symbolic enterprise has in fact grown increasingly explicit over time, with NATO declaring itself a ‘nuclear alliance’ in 2010. The following analysis develops two arguments. First, political responsibility for nuclear defence has shifted from individual member-states to the alliance as such; and, second, this development has been fuelled by member-states’ recurrent need to deflect criticism and adapt to the strengthening of humanitarian and anti-nuclear norms. The pulverisation of responsibility for nuclear defence in NATO has enabled pro-nuclear actors to justify costly nuclear modernisation programmes as acts of ‘alliance solidarity’ whilst exercising rhetorical coercion over advocates of denuclearisation.