All non-nuclear-weapon states are morally and legally obliged by the Nuclear Nonproliferation Treaty (NPT) to refrain from acquiring nuclear weapons. These obligations cannot be overridden for reasons of mere prudence. Only (i) material breaches of the treaty and/or a corresponding; (ii) ‘fundamental change in circumstances’ (rebus sic stantibus) that undermines the integrity of the NPT may override states parties’ legal nonproliferation duties. More than the violations of the NPT by ‘rogue’ states like North Korea or Iran, I argue that the failure of the de jure nuclear-weapon powers since 2001 to uphold their informal and some formal NPT commitments suggests the possibility of material breach and/or institutional subversion. If NPT subversion were to occur, the non-nuclear-weapon states’ collective responsibility to avoid complicity in that subversion leads them to choose between (a) individually seeking nuclear weapons capability for state security; or, more preferably, (b) a publicly announced and collective withdrawal from the NPT that simultaneously refuses to pursue the nuclear weapons option.Keywords: nuclear ethics; legal obligation - international treaties; obligation - international ethics; nuclear proliferation; withdrawal*international treaties; material breach - treaty obligations; subversion - treaty obligations(Published: 19 May 2009)Citation: Ethics & Global Politics, Vol. 2, No. 2, 2009, pp. 131-153. DOI: 10.3402/egp.v2i2.1916