Hmmm... Sachs seems to have forgotten the invasion of Hungary (1956) and Czechoslovakia (1968) and the pseudo-annexation of Transnistria, Abkhazia and South Ossetia in the early '90s....
On February 22nd 2014, the Ukrianian parliament voted to remove Yanukovych, including members of his own party. Yanukovych had fled shortly after signing the agreement with the EU and opposition the previous day. 5 days later, Russia invaded Crimea.