North Atlantic Treaty Organization
The North Atlantic Treaty Organization (NATO) is a military alliance of collective defence between 29 European and North American countries. It was motivated primarily by the threat of an attack by the Soviet Union.
The North Atlantic Treaty states alignment to the UN and the values of its charter. In particular the parties to the treaty agree to settle disputes peacefully.
The treaty was formed in 1949 by 13 of its current members. Since then many countries have joined. Particularly after the dissolution of the Soviet Union. Currently the US, Canada and 27 European nations have signed the treaty. Further European nations may join the treaty, as Article 10 constitutes an “open door” policy towards them.
NATO’s first military operation didn’t come until 1990, after the end of the cold war. The first time Article 5 - the treaty’s guarantee of collective defence - was invoked was in 2001 as a reaction to the September 11 attacks.
Over the years NATO’s has moved to a strategy it refers to as “Active Engagement, Modern Defence”. Since the beginning of the new millenium NATO has, among other, led military operations in Afghanistan and the African Union, training missions in Iraq, and disaster relief operations. However - in particular in the wake of the suspension of the INF treaty between the US and Russia - collective defence remains the NATO’s most integral component.
More information can be found on https://www.nato.int/