Wierd logic. On one hand you say a decisive end would be the best outcome, but what you don't say is that that is what was intended by Russia all along. A decisive end is what would have occurred, if we'd just accepted the Russian "Operation" was an internal affair between Russia and Ukraine, and hadn't got involved. What harm did it do to Crimea when that was reclaimed by Russia, with no shots fired? There never was any threat to Europe outside Ukraine. But there is now, and if it goes Nuclear then it is a threat to the world.