When the Soviet Union collapsed in 1991, it left Ukraine with borders that were a relic of Soviet propaganda, invented by Premier Nikita Khrushchev in 1954 as part of an effort to make the Warsaw Pact look like a diverse coalition of strong states.

In short, post-Soviet Ukraine wasn't a viable state. If Ukraine were going to break from Russia and join Europe, then it would need to adjust its indefensible borders. It could have political independence or territorial integrity, but not both.

Nearly 4 years later, the broad outlines of a peace settlement in Ukraine are exactly what they were in Feb 2022: territorial concessions to Russia in exchange for security guarantees from the West.