Nobody can do anything about it, Russia throughout history does whatever it wants for the benefit of Russia not the people but for Russia. They will not negotiate with other countries. You can't let Russia get sanctioned because Europe is very dependent on Russia's resources, heck countries like France and Germany only make about 35% of their electricity so imagine what would happen if Russia were to pull the plug on them. The only country who could get involved however is the U.S.A but they are reluctant on doing so. Even the U.S citizens don't want another war. Is it possible for a WWIII? Yes very possible. If this continues to take place then the world is indirectly giving appeasement to Russia while they gain land and resources. Russia will be even a bigger threat and EU countries are no longer the global powers they once were, they stopped investing as much in the military for a while now and became more diplomatic states. Russia on the other hand is heavily investing in the military and is not afraid to bombard anyone in their way.