When Ukraine was liberated in 1991, Ukraine had the world's third largest nuclear weapons fleet. Russia did not want a nuclear power to be established in its vicinity. That is why in 1994, a consensus was made. Budapest Memorandum. Ukraine gave all its weapons to Russia. In return, Russia gave its security guarantee.
Now after the Cold War NATO was slowly spreading to the Russian borders. Poland, Hungary, the Baltic countries all joined NATO. Russia felt that NATO was surrounding us. And when U