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.
Accession of Macedonia to NATO
The accession of Republic of Macedonia to NATO (North Atlantic Treaty Organization) is currently pending. NATO's invitation to the Republic of Macedonia was blocked by Greece at the 2008 Bucharest summit. NATO nations agreed that the country would receive an invitation upon resolution of the Macedonia naming dispute. Greece feels that its neighbor's constitutional name implies territorial aspirations against its own region of Macedonia. After the veto, Greece was sued in the International Court of Justice, over the use of "the Former Yugoslav Republic of Macedonia" as an acceptable option to enter NATO with, while Greece counterargues that it was a collective decision of NATO not to invite Macedonia and therefore the interim accord signed between the two countries was not violated. Greece may also block Macedonia's accession to the European Union over the naming dispute. Former United States Secretary of State Hillary Clinton has asked Macedonia and Greece to find an "acceptable solution" to the dispute, so that Macedonia will be free to join NATO. In 2014, prior to its 65th anniversary since its creation, NATO announced that it would not be offering any new countries membership into the organization that year. Some analysts, such as Jorge Benitez of the Atlantic Council think tank, argued that this reluctance was partly due to the new security climate after Russia's annexation of Crimea.