First thing you got to know about NATO, or the North Atlantic Treaty Organization, is that it is an intergovernmental military alliance which was signed on 4 April 1949.
Why was NATO created?
Actually NATO is the successor by the “Treaty of Brussels” which was signed on 17 March 1948 by Belgium, France, UK, Netherlands, and Luxembourg. This treaty and the Soviet Berlin Blockade led to the Western European Union’s Defence Organization.
However, participation of the US was necessary to counter an USSR attack. So now there were talks for a new military alliance. These talks led to NATO, signed in Washington D.C.
NATO members’ obligation in case of an attack
They agreed upon that NATO member being attacked are considered as attacks against them all. Consequently they agreed that, in case of such an attack, each of them will do whatever it takes to restore and maintain the security.
But this does not actually mean that the members will respond with military actions, since they don’t have to. (As opposed to the Treaty of Brussels which clearly stated that they have to aid militarily. Further, NATO has only to help above the Tropic of Cancer. (Which explains their non-interfere during the Falklands War.)
STANAG
The creation of NATO also brought along some standardization regarding military terminology, procedures and technology. To name one example, they used consistent.
Cold War
So during the Cold War 3 main events happened.
Firstly, the Korean War in 1950, which raised the threat level since all Communist countries were suspected to be in cahoots together. So in this connection, there was the Lisbon conference in 1952 for an expansion of NATO divisions.
1954, the Soviet Union suggested to join NATO. But NATO, fearing that the Soviet Union’s motive was to weaken the alliance, rejected this proposal.
One year later, in 1955, West Germany entered the alliance, based on the face that without Germany’s manpower it would be impossible to field