keiner?

en-Wikipedia schreibt "nation state"

The New Oxford Dictionary of E. schreibt ebenfalls "nation state".

I would NEVER rely on Wiki as a reliable source for orthography.

Merriam Webster Online prefers nation-state. There's possibly a Br-Am distinction.
Britannica also uses nation-state.

OED: nation-state

Anybody feel like correcting the Wikipedia entry?

http://www.onelook.com/?w=nation-state&ls=a
1. nation-state: American Heritage Dictionary of the English Language [home, info]
2. nation-state: Merriam-Webster's Online Dictionary, 11th Edition [home, info]
3. Nation-State, nation-state: Wordnik [home, info]
4. nation-state: Wiktionary [home, info]
5. nation-state: Encarta® World English Dictionary, North American Edition [home, info]
6. nation-state: Webster's New World College Dictionary, 4th Ed. [home, info]
7. nation-state: The Wordsmyth English Dictionary-Thesaurus [home, info]
8. nation-state: Infoplease Dictionary [home, info]
9. nation-state: Dictionary.com [home, info]
10. Nation-State: Wikipedia, the Free Encyclopedia [home, info]
11. nation-state: Dictionary/thesaurus [home, info]
12. nation-state: Nelson Political Science Glossary [home, info]
13. nation-state: Archaeology Wordsmith [home, info]
14. Nation-state: Geography Dictionary [home, info]

http://www.onelook.com/?w=nation+state&ls=a
1. nation state: Compact Oxford English Dictionary [home, info]
3. nation state: Macmillan Dictionary [home, info]
6. nation state (noun): Cambridge Advanced Learner's Dictionary [home, info]
info]
16. nation state: Political [home, info]
19. nation state: Urban Dictionary [home, info]
auch http://www.oxfordadvancedlearnersdictionary.c... ohne Bindestrich

Die Mehrzahl der Wörterbücher bei onelook.com verzeichnet die Bindestrich-Variante, die Mehrzahl der brit. WB die Schreibung ohne Bindestrich. Eine gewisse BE-Tendenz zur Version ohne Bindestrich gibt es also - ABER: http://www.britannica.com/EBchecked/topic/404...

The Wikipedia page is inconsistent. The heading (no hyphen) doesn't match with the article (with hyphen).

Given that the Oxford English Dictionary prefers the hyphenated version, I'd be careful about calling an AmE vs. BE difference here.

My first instinct was that we do still use a hyphen in both nation-state and city-state. Omitting the hyphen could be an invitation to confusion, since both parts of the compound, nation and state, probably also occur frequently on their own in the same contexts. However, in another light the hyphen could look a little old-fashioned; I don't feel that strongly about it.

In the first list above, only 1. AHD and 2. M-W are really independent, well-established dictionaries; 3. Wordnik is just an online word list, and 5. Encarta is sort of halfway in between, a computer-based dictionary. The other listings seem to be duplicates or inherently less reliable sources, unless one of them is masking what used to be Random House.

Maybe someone could check NOAD as another AE source; I'm not where mine is, sorry.

For the BE side it might be good to check Chambers as well, if OALD (newer) disagrees with OED (older). However, Chambers may now be merged with CALD, I'm not sure. Macmillan is evidently a relative newcomer; it's not yet clear how good it is, though it's handy in that it seems to have AE and BE versions.

If dropping the hyphen seems to be a more recent BE development, at least the OED and Britannica provide support for retaining it if you think it adds clarity.

@hm--us: Online-Chambers hat zu "nation(-)state" nichts zu sagen

Macmillan's handy in that it seems to have AE and BE
Ich hatte bisher den Eindruck, dass der einzig nennenswerte Unterschied beider Versionen die Sound-files sind (ganz subjetiv...)

Well, you may be right, I haven't tried Macmillan myself. But even sound files might be handy, since that's often half the AE/BE battle.

"nation state" is two words as far as I'm concerned.