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.
Ukraine–NATO relations
Relations between Ukraine and North Atlantic Treaty Organization (NATO) started in 1994. Ukraine applied to join the NATO Membership Action Plan (MAP) in 2008. Plans for NATO membership were shelved by Ukraine following the 2010 presidential election in which Viktor Yanukovych, who preferred to keep the country non-aligned, was elected President. Amid the Euromaidan unrest, Yanukovych fled Ukraine in February 2014. The interim Yatsenyuk Government which came to power, initially said, with reference to the country's non-aligned status, that it had no plans to join NATO. However, following the Russian military invasion in Ukraine and parliamentary elections in October 2014, the new government made joining NATO a priority.