The North Atlantic Treaty Organization (Nato) was created at the outset of the cold war, with its founding aims to act as a bulwark against the Soviet Union and guarantee the security of its members through political and military means.
At its core is the principle of collective security and the belief that an attack on one member is an attack against all, as enshrined in Article 5 of the treaty. Article 5 has been invoked only once – in response to the 9/11 terrorist attacks in the US in 2001.
