“Putin has troops in Kherson and seems to be thinking about taking everything from Crimea to Moldova.”
Yes, and Moldova.
Kaliningrad is another hotspot with Russian military forces there engaged in unusual movements which have the Lithuanian and Latvian governments concerned enough to request additional assistance from NATO and the United States.
One way to possibly deter Russian military adventures elsewhere is to place US consulates in threatened cities or even on major military bases, and have the host state declare them as sovereign American soil.
Might work; might not. Will never know until you try it. (Alamagordo, NM, 1945).