War win or lose

In 2008 President Bush announced that the west wanted Ukraine and Georgia to join NATO. Russia announced that such a move would be a bright red line in the sand and would lead to war and quite possibly nuclear war. Both Trump and Biden doubled down on this plan. For those who remember their history, warnings like this are not that uncommon and usually lead to war. Before WW 2 Japan, an island nation, needed raw materials to build up and maintain its infrastructure and so they invaded China. In response the US set out to embargo oil supplies to Japan and five months later Japan attacked Pearl Harbor. Russia was pushed into a corner and like a trapped animal responded. Now the world is stuck watching Ukraine be destroyed. This can only end in three ways. Russia can win and take over Ukraine or Russia can lose and go home with its tail between it legs. Third is a negotiated settlement. What will NATO do if Ukraine starts to lose and Kiev is taken over by the Russians. Will NATO troops be introduced to fend off the Russians. What if Ukraine wins. Will Russia just admit defeat and go home empty handed. Everyday the negotiated peace seems the only sensible solution.