Since the Eastern enlargement, following the end of the Cold war, the issue of the integration of Central and Eastern European countries (CEECs) in European union represents a major challenge for the existence itself of EU institutions. In addition to wide disparities in economic systems, the EU institutions are called to face the integration of systems characterized by important differences in perception of identity, as well as in value system in several topics. These differences resulted in several clashes between EU commission and CEEC States about migration, civil rights and in particular about the central topic of hierarchical relationship between nation-country and EU institutions. The explosion of the war in Ukraine has made urgent the importance to make stronger the ties between CEECs and European institution, in order to strengthen the Eastern border of Europe and ensure its ability to face the time war. The book collects contributions of researchers from Italy, Poland and Hungary, aiming at taking stock of the challenging geopolitical situation of CEE Countries at the time of international tension.