When discussing a treaty or international agreement, which is correct?

"There are 100 states party to the treaty." (for example, as used here)

Or: "There are 100 state parties to the treaty." (for example, as used here)

Or: "There are 100 states parties to the treaty." (for example, as used here)

  • I would have voted for the first one having never seen the other used. However there seem to be lots of examples of both the second and third so perhaps they are all correct.
    – dave
    Apr 22, 2015 at 1:24
  • 1
    "One hundred states are party to the treaty."
    – Hot Licks
    Apr 22, 2015 at 1:25
  • "States parties" looks like a direct calque of the French noun phrase "États partis". It may be diplomatic English but I am not sure it is standard English.
    – Henry
    Dec 1, 2020 at 11:26

3 Answers 3


The first two are both grammatical, and mean roughly the same thing, but are parsed slightly differently.

100 states party to the treaty

party to the treaty is being used as an adjectival phrase that describes the 100 states.

100 state parties to the treaty

parties is a noun, qualified by state, and to the treaty is a prepositional phrase that describes these 100 state parties.

Google Ngrams shows that states party to the treaty is slightly more common, although they've swapped positions a number of times over the past few decades. It sounds better to my ears, but that's just personal opinion.

100 states parties to the treaty

can't be parsed in either way. When a noun is used as a qualifier, it's normally singular. And parties is not an adjective, only party would be.

  • Of the first two, is one correct or preferable to the other?
    – user88040
    Apr 22, 2015 at 22:51
  • I prefer the first, but it seems that they're both similarly acceptable.
    – Barmar
    Apr 23, 2015 at 14:08

States parties is a term of art in public international law. It refers to the states that have signed a particular treaty. For example: states parties to the Treaty of Versailles.

It may not make sense from a purely grammatical perspective, but it is regularly used in international law. The first and second options are not commonly used in international legal material and would probably considered wrong if you are writing for a diplomatic or legal audience.

As an example: UNESCO, States Parties Ratification Status

States Parties are countries which have adhered to the World Heritage Convention.They thereby agree to identify and nominate properties on their national territory to be considered for inscription on the World Heritage List

For reference, explained by Karel:

In international law it is a term of art as stated above. You find examples of this in international treaties such as Article 4(1) of the International Covenant on Civil and Political Rights (ICCPR) which reads:

"In time of public emergency which threatens the life of the nation and the existence of which is officially proclaimed, the States Parties to the present Covenant may take measures derogating from their obligations under the present Covenant to the extent strictly required by the exigencies of the situation, provided that such measures are not inconsistent with their other obligations under international law and do not involve discrimination solely on the ground of race, colour, sex, language, religion or social origin."

  • 2
    This seems like a great insight into the question, but without any supporting evidence. Can you add supporting evidence? Maybe reference the relevant page in a legal dictionary?
    – MetaEd
    Jun 29, 2016 at 22:03
  • 1
    @Mark. My two examples both come from international organizations. There seems to be a variety of terms in use even amongst intergovernmental bodies, so without a source, I can' t know which is definitive.
    – user88040
    Jul 1, 2016 at 2:07

Personally, the first one sounds correct to me, but according to 100 years of books, parties to the treaty is correct. Party to the treaty is close behind though. I used Google Ngram Viewer to get these results. Either one is usable and it just depends on what fits better.

Edit: I've never seen the third one used and it doesn't sound right. I'd say stick to either the first or second one.

  • 1
    A concern with Google Ngram is it probably turned up examples from sentences like "there are five parties to the treaty" rather than "there are five state parties to the treaty". It would be better to search for the whole of "state[s] party[ies] to the treaty"
    – bcc32
    Apr 22, 2015 at 3:36
  • @bcc32 I got roughly the same results when I tried with state[s] added in. Also, that spike in the 1960s is quite intresting, anyone have any idea of what that's about? Apr 22, 2015 at 3:39
  • Hmm, based on the results, shouldn't you then prefer the first and third sentences, and not the second one?
    – bcc32
    Apr 22, 2015 at 3:41
  • 1
    Shoot, your right, I didn't read the graph correctly. Apr 22, 2015 at 3:51