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.
Nuclear escalation
NATO, is an alliance of nations that via three permanent members (USA, UK, and France) is a nuclear alliance. This alliance was formed in order to provide a blanket of security for Western European nations, Canada, and the United States against the Soviet Union. NATO members get the safety of Nuclear weapons being shared to its members from one of the 3 permanent members. However, the U.S. was the primary defender of the other countries upon NATO's formation, due to its vast nuclear arsenal that it lays at the disposal for the organization. NATO's escalation policies did not take hold until the late 1950s. During the previous time the weapons and capabilities of NATO's combined members alongside the U. S's vast nuclear arsenal were enough to keep their citizenry calm. NATO policy would amalgamate from the U. S's initial nuclear strength. Russia lacked ICBM's or long range missiles to directly threaten the U.S. In contrast, the U.S. had stationed bombers within NATO countries in Europe that could deliver nuclear payloads to designated targets within the Soviet Union if they attempted to start a war. One of these was the U.S. Corporal missile with a range of 120 kilometers (70–80 miles) and had a one kiloton warhead. After the late 1950s the USSR was able to raise its Nuclear arsenal and delivery methods to have the U.S become a capable target. Many of the European NATO countries became worried that the US's massive firepower was equaled by the USSR and that the United States would have no reason to come to European aid with the new possibility of any attack from the U.S being met in kind with similar or greater means of nuclear arms directed at the U.S. created NATO's response of ‘Massive Retaliation’.