Related Clues:
- Alliance based in Brussels: Abbr
- Defense grp. that's an anagram of 40-Across
- Grp. that added North Macedonia in 2020
- 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
- 'November Alfa Tango Oscar'
- 30-country alliance
- Grp. spelled using its own alphabet at the starts of 19-, 29-, 43- and 50-Across
- Group of countries taking part in a tournament
- 30-country military grp
- Postwar mil. alliance