The West must not give in to Putin's nuclear rhetoric. By ratcheting up fear, Putin is hoping we back off and let him have his way in Ukraine. However, doing that would only further embolden the Russian president. We must be firm and resolute in the face of this nuclear blackmail.
Russia is simply following the lead of the US which for years has stationed nuclear weapons in the territories of its allies. Why should Russia not be inclined to do the same?