The international community that brings together civilized politicians and strategic experts generally accepts the sacramental maxim that “nuclear war cannot be wan and it should never be fought” and that “nuclear weapons—as long as they exist—should serve to deter aggression and prevent war”. However, these well-intentioned principles are easier to proclaim than translate into practical policy. While the development of all nuclear weapons in all countries is justified by the imperative of deterrence, all of these weapons are, in fact, designed for the actual conduct of nuclear war, thus serving as a material basis of the doctrines of nuclear deterrence. Depending on the scenarios of using nuclear weapons, under the influence of technological development and amid intense international conflicts, these deterrence doctrines undergo frightening transformations (metamorphoses), turning into their opposite, i.e. plans and practical options of unleashing a nuclear war. Recently, this has been manifested in the Russian strategic discourse on ways to quickly and successfully complete the military special operation in Ukraine. Such initiatives are prone with the danger of Russian national suicide. There is no acceptable alternative to a peaceful settlement of the Ukrainian conflict, and disagreements on its terms are not worth the risk of a nuclear apocalypse. It is only through nuclear arms reduction and limitation treaties that nuclear deterrence and nuclear warfare can truly be separated. Nuclear forces and weapon systems covered by such agreements primarily serve the purpose of deterrence, while those remaining outside arms control predominantly embody means and plans of nuclear warfighting.