I also believe that he is sending a message to the Nations that are agreeing to have the abm system installed. [To Wit] The United States will not protect you. When we decide to come after you, you will be on your own.
I intentionally omitted NATO because without the United States, NATO could not whip a Troop of Girl Scouts.
This was , again, in my opinion, not a spur of the moment decision on Putin’s part. He has been planning this for months.
A lot is at stake here.