It’s harder because US troops are in Poland
What some people believe, once the Russians invade the Ukraine...there’s the Kaliningrad situation (a Russian ‘property’), which requires logistical support that comes from Belarus/Russia, and has to pass via Lithuania (about 75 miles). Some people believe military hardware will be driven in that direction, and will be halted at the Lithuania border.
Basically, the next trip-wire.
US/Polish troops on the NE of Poland would then be involved in this military situation. It doesn’t end in the Ukraine.