NATO
The Western military alliance of 1949 whose Article 5 says an attack on one member is an attack on all.
What the paper can ask
- Founded 4 April 1949; 32 members today, 30 in Europe and two in North America. (as of 23 Oct 2026)
- Article 5 collective defence has been invoked only once, after the September 11 attacks.
- Headquarters Brussels; Secretary General Mark Rutte; military HQ (SHAPE) near Mons. (as of 23 Oct 2026)
- Members committed in 2025 to spend 5 percent of GDP on defence by 2035, up from the 2 percent target. (as of 23 Oct 2026)
Why exams ask
Founding year and number of founders, newest members, headquarters and Article 5 are standard.
The full story
The North Atlantic Treaty Organization (NATO) was created by the North Atlantic Treaty signed in Washington on 4 April 1949, at the start of the Cold War, to counter the Soviet Union (which answered with the Warsaw Pact in 1955). Its heart is Article 5: an armed attack on one member is treated as an attack on all; it has been invoked once, after the 11 September 2001 attacks.
Test yourself
1.How many founding members did NATO have when the North Atlantic Treaty was signed on 4 April 1949?
Correct. The 12 founders were the five Western Union states plus the US, Canada, Portugal, Italy, Norway, Denmark and Iceland.
Not quite. The 12 founders were the five Western Union states plus the US, Canada, Portugal, Italy, Norway, Denmark and Iceland. It goes into your error book.