Enlargement of NATO
As of 2018, NATO officially recognizes four aspiring members: Bosnia and Herzegovina, Georgia, Macedonia and Ukraine. The Federation of Bosnia and Herzegovina within Bosnia and Herzegovina has expressed willingness to join NATO, however, it faces consistent political pressure from Republika Srpska, the other political entity in the country, alongside its partners in Moscow. Macedonia has been prevented from joining the alliance by Greece, one effect of the Macedonian naming dispute. Future expansion is currently a topic of debate in several countries outside the alliance, and countries like Sweden, Finland, and Serbia have open political debate on the topic of membership, while in countries like Ukraine, support and opposition to membership is tied to ethnic and nationalist ideologies. The incorporation of countries formerly part of the Eastern Bloc and the Soviet Union has been a cause of increased tension between NATO countries and Russia.
Enlargement of NATO
A CeSID poll in June 2015 conducted with the support of the United States Agency for International Development (USAID) indicated that only 12 percent of those polled supported for NATO membership, down from 25 percent in 2012, and 73 percent were opposed. The minor Liberal Democratic Party and Serbian Renewal Movement remain the most vocal political parties in favor of NATO membership. Although Serbia aspires to join the European Union, Serbia may seek to maintain military neutrality, joining neither NATO nor the Collective Security Treaty Organization (CSTO).