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Twelve nations signed the North Atlantic Treaty, establishing NATO, an international military alliance whereby its member states agree to mutual defense in response to an attack by any external party.
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North Atlantic Treaty
1949 treaty forming the basis of NATO
The North Atlantic Treaty, also known as the Washington Treaty, forms the legal basis of, and is implemented by, the North Atlantic Treaty Organization (NATO). The treaty was signed in Washington, D.C., on 4 April 1949.Source: Wikipedia (CC BY-SA)
NATO
Intergovernmental military alliance
The North Atlantic Treaty Organization, also called the North Atlantic Alliance, is an intergovernmental military alliance between 32 member states—30 in Europe and 2 in North America. Founded in the aftermath of World War II, NATO was established with the signing of the North…Source: Wikipedia (CC BY-SA)
Military alliance
Alliance between different states with the purpose to cooperate militarily
A military alliance is a formal agreement between nations that specifies mutual obligations regarding national security. In the event a nation is attacked, members of the alliance are often obligated to come to their defense regardless if attacked directly. Military alliances…Source: Wikipedia (CC BY-SA)
Collective security
International security arrangement
Collective security is arrangement between states in which the institution accepts that an attack on one state is the concern of all and merits a collective response to threats by all. Collective security was a key principle underpinning the League of Nations and the United…Source: Wikipedia (CC BY-SA)