Related Clues:
- Grp. joined by North Macedonia in 2020
- Brussels-based gp
- Grp. founded to resist Communism
- Alliance based in Brussels: Abbr
- Defense grp. that's an anagram of 40-Across
- Grp. that added North Macedonia in 2020
- Alliance with a DC HQ
- US alliance with European nations
- Org. with a phonetic alphabet
- Alliance formed in April 1949
- Alphabet where X is 'X-ray'
- Security alliance
- Pact since '49
- Intl. alliance since 1948
- 'November Alfa Tango Oscar'