| During the Russian invasion of Ukraine, several senior Russian politicians, including President Vladimir Putin, Foreign Minister Sergey Lavrov, and former president and prime minister Dmitry Medvedev, have made several statements widely seen as threatening to use nuclear weapons. This frequent warning of nuclear conflict is, of course, a matter of concern. Moscow’s defence doctrine envisages a nuclear response even to an attack with conventional weapons that “threatens the very existence of the Russian state.” That wording is deliberately vague to force the West to take the warnings more seriously. On 6 May, Putin announced he had authorised a military exercise involving the deployment of tactical nuclear weapons in southern Russia. He claimed there was “nothing unusual” about such a planned training exercise, but its location indicates it is linked to Ukraine. A tactical nuclear weapon or non-strategic nuclear weapon is a nuclear weapon designed to be used on a battlefield in military situations, mostly with friendly forces in proximity and perhaps even on contested friendly territory. However, tactical and strategic nuclear weapons are similar. Nuclear weapons have not been used since the United States unleashed the atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August 1945, the two deadly blasts qualifying for the category “tactical”. The explosive yield of tactical nuclear weapons can range from under one kiloton to about 100 kilotons, whereas strategic nuclear weapons can have a yield of up to one thousand kilotons. The bombs that destroyed Hiroshima and Nagasaki were “only” between 12 and 21 kilotons. Russia likes to distinguish between tactical and strategic nuclear weapons as if it could play with its tactical nuclear arsenals, achieve its goals, and call a truce. Conversely, for the West, once the nuclear threshold is reached, global Armageddon can hardly be avoided. | 
