That's all he has now. Gone straight to using nuclear threats. He's running out of troops and weapons so it's in desperation that he threatens weapons of last resort. After 12 months the Russian Army has not been able to over run a smaller country and has been humiliated that if failed its invasion and had to retreat. Over 100,000 dead troops and thousands of pieces of hardware are gone. It will be upto the Russian Generals what's left of them, if they are willing to allow Putin to sacrifice Russia for some personal vendetta against the "immoral" West.