The creation of nuclear weapons for the first time in the history of humankind put under threat the very existence of contemporary civilization. The negotiated legal norms of nuclear arms control have become a man-made tool for preventing this threat. During the last 65 years, a grandiose architecture of the international cooperation has been built by the efforts of many states. This is the greatest historic achievement of humankind. This system has incorporated an overwhelming majority of United Nations member states. Talks on nuclear arms have resulted in dozens of treaties and agreements, which have reduced the number of nuclear weapons almost by an order of magnitude, stopped their testing, and limited their proliferation. Nonetheless, during the last decade the architecture of nuclear arms control has entered a stage of disintegration. The reasons lie in a drastic escalation of tensions in great powers' relations, a changing world order and the development of advanced weapon systems and disruptive technologies. Donald Trump's return to power in the U.S. has up till now provided no certainty regarding the preservation or renewal of nuclear arms control. Meanwhile, the transition to multipolarity presents much higher requirements for such a system. If it fails to emerge, the polycentric world will turn into a stage of global nuclear chaos.