Then why did Russia sign away sovereignty and border rights to Ukraine in 1994?
https://nzhistory.govt.nz/media/photo/map-russian-empire-1914
https://vividmaps.com/old-maps-of-russia/
https://en.wikipedia.org/wiki/Tsardom_of_Russia
https://en.wikipedia.org/wiki/Wild_Fields
Uhh, Regan broke the Soviets and Russia had no choice