After all, Ukraine was part of the Soviet Union (Russia essentially) for 70yrs and it didn’t affect US national security one diddly squat.
The Cold War was neither necessary or unnecessary. It was a defacto post WWII reality when the Soviet Union decided under Stalin and his heirs, to control by ideology and force Eastern European countries, and also attempt to destabilize other countries worlwide to the detriment of US national security interests. Ukraine (and its territory) did nothing to add or subtract from our national security concerns during those 70 years. The point being, that if Ukraine were to have a fully compliant government today to the Russians, it will make no difference to the US national security interests.