NATO
New membership in the alliance has been largely from Central and Eastern Europe, including former members of the Warsaw Pact. Accession to the alliance is governed with individual Membership Action Plans, and requires approval by each current member. NATO currently has two candidate countries that are in the process of joining the alliance: Bosnia and Herzegovina and the Republic of Macedonia.
In NATO official statements, the Republic of Macedonia is always referred to as the "former Yugoslav Republic of Macedonia", with a footnote stating that "Turkey recognizes the Republic of Macedonia under its constitutional name". Though Macedonia completed its requirements for membership at the same time as Croatia and Albania, who joined NATO in 2009, its accession was blocked by Greece pending a resolution of the Macedonia naming dispute. In order to support each other in the process, new and potential members in the region formed the Adriatic Charter in 2003. Georgia was also named as an aspiring member, and was promised "future membership" during the 2008 summit in Bucharest, though in 2014, US President Barack Obama said the country was not "currently on a path" to membership.
Enlargement of NATO
While the other Visegrád members were invited to join NATO at its 1997 Madrid summit, Slovakia was excluded based on what several members considered undemocratic actions by nationalist Prime Minister Vladimír Mečiar. Romania and Slovenia were both considered for invitation in 1997, and each had the backing of a prominent NATO member, France and Italy respectively, but support for enlargement was not unanimous, particularly in the US Congress. In an open letter to US President Bill Clinton, more than forty foreign policy experts including Bill Bradley, Sam Nunn, Gary Hart, Paul Nitze, and Robert McNamara expressed their concerns about NATO expansion as both expensive and unnecessary given the lack of an external threat from Russia at that time.