https://mondediplo.com/2022/04/03nuclear
Not obiter dicta but mens rea in a way that Putin is fearless and intends to frighten the west. See article.
Some trace the US’s caution back to a statement by Russia’s president Vladimir Putin on 24 February: ‘No matter who tries to stand in our way or … create threats for our country and our people, they must know that Russia will respond immediately, and the consequences will be such as you have never seen in your entire history.’ These words, and his order that Russia’s nuclear forces be placed on high alert (‘a special regime of combat duty’), amounted to attempted coercion, and could suggest that Biden’s reaction constituted backing down
