Alsace and Lorraine (formerly German speaking parts of France) were “fully annexed” parts of Germany, twice. They are not German now, and the language which was so prevalent is now secondary at best. It took 74 years and three wars to settle that particular dispute.
Regardless of who wins the current conflict, Russia and Ukraine will continue to spar over this territory. Too many FReepers think this is a contest between corrupt leaders. But it’s not, if past experience is any guide, Mr. Putin’s adventure has created a deep seated enmity that will grip the Ukrainian people in ways the neither they, he or Russian people will completely understand for years. If they lose this war, there will be at a minimum an insurgency, a nasty bloody affair to bleed Russia by a thousand cuts.
Additionally, any victory will not likely survive long after Mr. Putin’s eventual death. Therefore the Duma’s rubber stamp is meaningless, this question will be settled by force of arms. Which may take decades.
That is a bad analogy given the Crimea was very much Russian for more than 150 years, from before Texas was a state, for comparison. It was only made part of the Ukraine SSR as part of the USSR in the 1950s, because Khrushchev was from Ukraine and was calling the shots in the USSR, and made that administrative change.