Given the increase in mobilization in Russia signaling even greater commitment by Putin and his regime to succeed in their aggressive war in Ukraine, concerns about the potential use of nuclear weapons by the Russian aggressions have increased as well. In a release by the Atlantic Council some time ago, a number of experts presented several scenarios for how Putin might utilize nuclear weapons.
According to Keir Lieber and Daryl Press, Putin would utilize nuclear weapons as a way to send a message to the international community that Russia will not accept a devastating defeat in Ukraine, and as such the United States and its allies need to back off from providing support to the regime in Kyiv. That being said, both experts asserted that the nuclear weapons themselves would be used on Ukrainian territory, and against military targets, rather than against a NATO state. In addition, they suspect that Russia would seek to maximize some military advantage in the strike, so they might detonate half a dozen low-yield air bursts against entrenched Ukrainian positions, which would also minimize the fallout of the strikes.
An alternative scenario was put forth by Walter Slocombe, in which he suggested that Putin might act first to intimidate, such as with the deployment of nuclear forces to a location like Kaliningrad, or a demonstration at a Russian nuclear testing range to remind the international community what options Putin might consider in the war. Should the actual use nuclear weapons occur, Slocombe reiterates the points of Lieber and Press regarding a Ukrainian target, something that Alexander Vershbow and Jan Lodal agreed with as well as adding that such an attack would likely attempt to minimize civilian casualties to avoid goading the West into a response. Mark Cancian has more recently stated that the front lines of the conflict would make the most sense. This might mean the deployment of tactical nuclear weapons by Russia, which range from 0.3 kilotons to 100 kilotons in explosive power. Designed to have a more limited impact on the battlefield, these weapons fall far short of the measurements of the greatest weapons still held by Russia and the United States.
Regardless if one, or any of these scenarios, comes to pass, there is one greater concern for the world if nuclear weapons are used that will last after the war in Ukraine eventually ends. Since the end of the Second World War, there has existed a nuclear taboo such that no nuclear armed state has used these weapons first in any armed conflict they have engaged in. Should Putin decide to use a nuclear weapon in an attempt to stave off a disastrous defeat, and the threat it would pose to his survival, then the future likelihood of another state making the same decision is that much higher. And that is a threat to the safety of everyone.