So what? That "one Ukraine" map is a snapshot in time. Those external national borders have been moved over and over in the past century. Crimea was part of Russia for 200+ years until Khrushchev literally gave it to Ukraine in 1954 as part of internal USSR politics. Crimea is less Ukrainian than Hawaii is American.
You would start WW3 over Russia reasserting control over Ukraine, with Putin undoing Khrushchev's unilateral "gift" in 1954?
