The first time that Article 5 of the North Atlantic Treaty had to be invoked was in response to

A) Japan's 1941 attack on Pearl Harbor.
B) a 1964 North Vietnamese attack on a U.S.naval vessel in the Gulf of Tonkin.
C) Saddam Hussein's 1990 invasion of Kuwait.
D) the September 11,2001,attack on the United States.

North Atlantic Treaty

An agreement that established the North Atlantic Treaty Organization (NATO), a military alliance designed for collective defense against aggression.

Article 5

A provision within a document or constitution which details specific processes or regulations, such as Article 5 of the NATO treaty which outlines the principle of collective defense.

September 11

Refers to the terrorist attacks that occurred on September 11, 2001, in the United States, particularly targeting the World Trade Center in New York City and the Pentagon.