One of the most common tactics used in conflict is to target and destroy the most treasured asset of the other side. When the “must have” thing is in danger, folks do weird things. Like Neville Chamberlain did coming back from Munich.
Chamberlain was not a fool. But his dear brother had bee killed in the first great war, and above all, he wanted to avoid another one. So he was easy prey for Hitler.
I fear that western leaders are similarly locked into fear of conflict these days. They seem to believe that they can bargain with Putin. The bargaining is likely to continue. Indeed, I see from NYT that Ukraine has worked out a cease fire deal that may or may not hold. The Telegraph suggests that the deal is a win for Putin. But we should not kid ourselves that Putin will change his attitude via bargaining. This is not likely.