Member states of NATO members and three former Yugoslav republics) from 12 March 1999 to 5 June 2017. NATO has added new members seven times since its founding in 1949, and since 2017 NATO has had 29 members. Twelve countries were part of the founding of NATO: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States. In 1952, Greece and Turkey became members of the Alliance, joined later by West Germany (in 1955) and Spain (in 1982). In 1990, with the reunification of Germany, NATO grew to include the former country of East Germany. Between
Montenegro–NATO relations Ratification (Resolution of Advice and Consent to Ratification (Treaty Doc. 114-12)) on 28 March 2017. President Donald Trump signed a presidential memorandum on 11 April 2017. Ratification by each member state was completed with Spain's ratification on 10 May. On 28 April 2017 Montenegro's parliament ratified the accession treaty. Montenegro officially joined NATO as a member state on 5 June 2017. The reaction of the Russian government to Montenegro′s bid to join NATO had been increasingly hostile culminating in an attempt to stage a coup d'état on 16 October 2016, on the day of the parliamentary election that allegedly would