Russia's military attack on Ukraine and the annexation of the four regions of Donetsk, Luhansk, Kherson and Zaporizhia to the Russian Federation is considered the largest military conflict in Europe after World War II, which explains why the military confrontation between Russia and Ukraine and the annexation of these regions to the Federation makes it necessary. Therefore, the main purpose of this article is to answer the questions that firstly, why Russia decided to attack Ukraine and annexed Donetsk, Luhansk, Kherson and Zaporizhia to the Russian Federation and secondly, what are the causes of the spread of the crisis and the success of these annexations? In response to this hypothesis, the reason for Russia's decision to attack Ukraine and annex these areas to Russia was to eliminate the threats caused by Ukraine's possible membership in NATO, also, the changes in the common values and norms between Ukraine and Russia during the crisis and commonalities and links between the Russian society and the societies of these regions have played an important role in the spread of the crisis and the success of annexations.To answer the research questions, the method of multiple case study and theories of balance of threat and constructivism have been used. The data was also collected in a library method and analyzed with a descriptive-analytical approach. The findings of the article shows that both material and immaterial factors played a role in Russia's military attack on Ukraine and the annexation of these areas to the Russian Federation.