Russia quaranteed the souvereignty of ukraine and its borders with the budapest memorandum: https://en.wikipedia.org/wiki/Budapest_Memorandum_on_Security_Assur

Russia quaranteed the souvereignty of ukraine and its borders with the budapest memorandum: https://en.wikipedia.org/wiki/Budapest_Memorandum_on_Security_Assurances https://en.wikipedia.org/wiki/Budapest_Memorandum_on_Securit... Russia guaranteed ukraine free choice of alliances with: https://en.wikipedia.org/wiki/Paris_Charter https://en.wikipedia.org/wiki/Paris_Charter There is no chance of NATO acceptance while there are still ongoing territorial disputes like crimea and donbas. Solving those could take decades if not longer. Putin himself has said that the ukrainian state is a historical mistake and has no claim to statehood. He just wants some juicy bits of strategical importance like a land connection to crimea and a broken country as a buffer zone that he can show to other aspirants what happens if you misbehave.