It has probably been repeated more than a dozen times on this thread; however I think it requires repeating. As a reader, and lover, of history, this reminds me of the early days leading up to World War Two (and no I am not beating any war drums, I wish to avoid it). The world did not approve Hitler’s action in the Austria, Sudetenland and later in Czechoslovakia, but let it slide. There also were quite a few eager individuals that presented Hitler’s version of the story rather than stopping him. I believe we have all learnt Hitler’s version the hard way. Putin (accept it or not) is a new Hitler on a smaller scale; it hurts to see that so many people do not mind that part of history is repeating itself. If it does, that is due to our indifference and ignorance, which is hardly an excuse.
Unfortunately leaders in the West have let too many lines in the sand be crossed with no real sanction.
This time the West and Europe in particular need to actually surprise Putin. This may well mean sanctions that really hurt both Russia and the West. However, if we want a safer world we have to be prepared to pay the cost. Because the cost of not stopping this type of aggression will be even costlier.