What is NATO, and why is it important?

What does NATO stand for? 

NATO is an acronym for the North Atlantic Treaty Organization, a military alliance established in 1949.

Twelve founding members signed the North Atlantic Treaty at the time: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States.

NATO was launched as "part of a broader effort to serve three purposes: deterring Soviet expansionism, forbidding the revival of nationalist militarism in Europe through a strong North American presence on the continent, and encouraging European political integration," its website says.

What is NATO's goal? 

The alliance says its "essential purpose is to safeguard the freedom and security of its members through political and military means."

How many members does NATO have? 

Twenty eight. Greece, Turkey, Germany, Spain, the Czech Republic, Hungary, Poland, Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, Slovenia, Albania, and Croatia have all joined.

How does collective defense work? 

If one NATO member is attacked, it's viewed as attacking the rest of the members. The idea is expressed in Article Five of the North Atlantic Treaty.

NATO members "will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force," according to the article.

The article was invoked for the first time in the wake of 9/11.

Where are the NATO headquarters? 

NATO is headquartered in Brussels, Belgium.

Who is NATO's Secretary General? 

The former Prime Minister of Norway, Jens Stoltenberg, serves as its Secretary General. He's expected to chair committees, direct discussions, and make sure decisions go into effect, according to the alliance.

How does NATO defense spending work? 

For NATO members, there is a target to spend 2 percent of their gross domestic product (GDP) on defense. Five members - Estonia, Greece, Poland, the United Kingdom, and the United States - meet that goal.