Putin has had his media repeatedly stress that while Soviet military doctrine precluded offensive nuclear options, modern Russia reserves the right of nuclear first strike capability for any reason.
They're going to the Baltics next, then Poland. Any further "negotiations" will just embolden him to expand Warsaw ~1986 boundaries. Don't forget, Putin considers Berlin as rightfully his.
As for "what we're going to do about it"... Come on.... Doesn't everyone remember the famous hot-mike incident in 2011 when Obama told him to wait until after he got relelected, then he'd let Putin do whatever he wanted?
This is a good read on the current situation. The Economist, noted for its rather thoughtful, restrained insights on aggressive foreign policy, nails it. Now or later, we're going to war with this guy.
Bookmarks