Crimea cannot be re-supplied from Russia except by sea. So Russia needs to invade Eastern and Southern Ukraine to be able to re-supply Crimea BY LAND. that’s the reason Putin wants to invade East/South Ukraine and he’s bringing fighters and bombers into Western Russia. the Wall Street Journal showed commercial satellite photo’s HERE along with a map of Ukraine and Western Russia that shows where the Russian Military is.
What’s going to happen in Eastern/Southern Ukraine? No one knows at the moment but it seems easy to conclude that Putin want’s to rush in. (It’s a horrible pun)