NATO, established on April 4, 1949, is a Western security alliance comprising 12 original members: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States.

The alliance was formed by signing the Washington Treaty, deriving its authority from Article 51 of the United Nations Charter, which upholds the inherent right of independent states to individual or collective defense.

Central to NATO is the principle of "collective security," where an attack on any member nation is viewed as an attack on all, necessitating collective response. This principle emerged from the Cold War context of the late 1940s, amid the rivalry between the USSR and the US over ideological and economic dominance. Article 5 of the Washington Treaty, addressing collective security, was introduced to counter the perceived threat of Soviet expansionism beyond Eastern Europe. In response, the USSR formed the Warsaw Pact in 1955, uniting socialist countries as allies.

However, invoking Article 5 does not mandate uniform military action by all member states. The extent of intervention is determined by each country "as it deems necessary." To date, the only instance of Article 5 being activated was in response to the September 11, 2001 attacks on the US, leading to NATO's deployment in Afghanistan for nearly two decades

3. Who are NATO’s members today?

In addition to the initial 12 members, subsequent additions to NATO's membership include Greece and Turkey in 1952, West Germany in 1955 (later recognized as Germany), Spain in 1982, the Czech Republic, Hungary, and Poland in 1999, followed by Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia in 2004, Albania and Croatia in 2009, Montenegro in 2017, North Macedonia in 2020, Finland in 2023, and Sweden in 2024.

A surge of new members joined in 1999, a few years after the dissolution of the Soviet Union in 1991, prompting concerns about the alliance's potential obsolescence due to the absence of its original purpose

4.What challenges does NATO face today?

• During the 2019 commemoration of NATO's 70th anniversary, notable tensions arose among member nations.
• President Donald Trump of the United States emphasized the necessity for countries to increase their military expenditures.
• This call stemmed from a 2014 agreement among NATO members to allocate a minimum of 2 percent of their Gross Domestic Product (GDP) to defense spending, a commitment made following Russia's annexation of Crimea.
• However, only a handful of nations met this threshold, prompting criticism from President Trump who deemed it unfair, particularly to countries such as the US that were fulfilling their spending obligations. By 2023, among the 30 member countries at the time, only 11 exceeded the stipulated limit.
• One significant catalyst for increased defense spending was the Russian invasion of Ukraine the preceding year. Even traditionally neutral countries in foreign policy, such as Finland and Sweden, found appeal in the concept of collective security in response to Russia's assertive actions.
• Despite NATO's "open door" policy toward membership, the admission of new applicants requires unanimous approval from all member states. Turkey hesitated to support the applications of Sweden and Finland due to past criticisms from their politicians regarding Turkey's human rights record. Turkey also accused these nations of harboring "terrorists"