Ukraine has struggled to free itself from the terrible oppression and sucking dry of its natural resources by Russia for most of its existece. It's geography, which include flat, fertile, moist plains that have the seasonal ability to grow most of the food Russia needs to survive, and its location along the strategic Black Sea coast, which is Russia's main ice-free access to the Atlantic Ocean, have given it the disadvantage of having suffered under Russian domination, Czarist or Communist, both totalitarian, for much of its existence. So when the opportunity afforded itself, and the Soviet Union collapsed, the areas that are part of the historic territory of Ukraine united under a democracy for the first time in over a thousand years.

So when the rarest of rare opportunities came for the Ukrainian people to declare independence on August 24, 1991, they did it. The boundaries of the country reflect all areas where the majority of the population affirmed the declaration by referendum, and this was followed by recognition of 68 countries before the end of 1991. What occurred then is therefore legal, and recognized, establishing a border around a country that is entitled to exist independently, and whose sovereignty should be defended by other countries including the superpower United States.

The United States needs to take the lead in establishing a just peace by pressuring Russia to accept a treaty that includes the following:

The restoration of all territory within the boundaries of Ukraine established on August 24, 1991, including the Donbas, and the Crimea to the Ukrainian national government.
The recognition, by Russia, of Ukraine's sovereignty, and of its independence, which includes its right to pursue membership in the NATO alliance.
Resolution of all of the issues regarding access of the Russian navy to Ukraine's Black Sea ports, including Sevastopol on the Crimean peninsula.
The return of all war prisoners, along with the Ukrainian civilians, mostly children, who have been kidnapped and spirited off into Russia.
Reparations equal to the amount of war damage inflicted on Ukrainian property during the war.
A treaty establishing permanent peace between Russia and Ukraine.