Putin will use nuclear weapons in Ukraine, and their use will convince Germany --- as the chief economic and political leader of Europe --- of the need for its own nuclear deterrent (a few American nukes are currently on German soil) as well as the need for greater European unity. And if the German political climate changes and Germany becomes more militaristic, we need only look at the first half of the 20th century to see what can happen. Germany today is a pacific liberal democracy and hopefully will remain that way. But history sometimes takes some weird turns, and if push comes to shove then things can change dramatically.