Amid successful counterattacks by Ukrainian forces in the east of the country, there are concerns that Russia could resort to using nuclear weapons (Economist, BBC, Guardian). A radiological device (aka "dirty bomb") would not count (Mass.gov). For the purposes of this question, "Ukraine" includes the boundaries generally recognized by the international community, including Donbas and Crimea.

This market is a copy of The World Ahead forecasting challenge by Good Judgement and The Economist.