Are you willing to go to war with Russia over Ukraine?
Yes.
Ukraine should invite a handful of troops each from as many countries as possible, to camp along the border. If Putin breaks any of their toes then the answer to your question is yes. Putin should be well informed that every country will consider that an act of war, and that they will all immediately mobilize all forces necessary. Don't waste anyone's time explaining consequences to me, I'm not stupid. Putin is an uncivilized psychopath, but he is not stupid. If he somehow WERE that stupid, there's no point in putting that off 'til tomorrow.
23 August 1939 Russia formed a treaty with the Nazis, dividing territories of Romania, Poland, Lithuania, Latvia, Estonia, and Finland into German and Soviet "spheres of influence", anticipating potential "territorial and political rearrangements" of these countries. Less than a month later Russia invaded Poland, and proceeding with annexation of Finnish, Estonian, Latvian, Lithuanian, and Romanian territories.
Putin grew up as Soviet KGB, and he still thinks in archaic cold war terms. He wants to violently rebuild the Soviet Empire - if he thinks he can get away with it.
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