Russian government publish a document describing the condition of use of their nuclear weapons:   Link to the document   Sadly it's an image PDF so it's not possible to put it through a translator, though some news sites published some excerpt.   https://www.defensenews.com/global/europe/2020/06/02/new-russian-policy-allows-use-of-atomic-weapons-against-non-nuclear-strike/   https://www.kommersant.ru/doc/4365411   http://www.opex360.com/2020/06/0