Two years ago, had someone said Putin would invade Ukraine and then that he would annex Crimea that person would have been called crazy. How do I know this? Because I was that person! But it happened and it is still happening. With the collapsing Russian economy entirely dependent on energy exports and the price of oil so low, Putin is desperate for foreign conflicts so the his propaganda can be filled with anything except news about Russia.
The last 16 years are a long list of Putin doing things that people said Putin would “never do”. (Khodorkovsky, Litvinenko, Pussy Riot, Georgia, 2012 return, Ukraine, Syria, Turkey…) I don’t think he is desperate enough yet to cross a NATO border, but the idea that it’s “crazy” to suggest it might happen as things get worse in Russia is dangerously foolish. Putin has nothing to lose, no way back, and if he falls from power his fortune and likely his freedom or life will be lost. Dictators don’t have the luxury of thinking long-term or strategically, they have to worry about tomorrow while keeping an eye over their shoulder. I travel to the Baltics frequently and they have no illusions there about what Putin is capable of.