North Atlantic Treaty is the treaty that brought NATO into
existence, signed in Washington, DC on April 4, 1949.
The original twelve
nations that signed it and thus became the founding members of NATO
Map of NATO countries chronological membership.
Later the following nations joined:
Germany was reunified in 1990, the country as a whole
became a member of NATO.
April 2008 summit in Bucharest, Croatia and Albania were
officially invited to join NATO.
They both signed the treaty
and officially joined NATO on April 1, 2009.
The key section of the treaty was Article V which committed each
member state to consider an armed attack against one state to be an
armed attack against all states. The treaty was created with an armed
attack by the Soviet
Union against Western Europe in mind, but the mutual
self-defense clause was never invoked during the Cold War. Rather, it was invoked for the first time
in 2001 in response to the September 11, 2001 attacks
against the World Trade
Center and The
Pentagon in Operation Eagle Assist.
In the United States, the treaty was approved by the Senate
in a vote of 82 to 13 on July