The Hague Conference on Private International Law has recently published a helpful table showing which states have made an Article 23 declaration, and what kind of declaration they have made. Article 23 is the bête noire of American lawyers seeking documentary discovery abroad: it provides:
A Contracting State may at the time of signature, ratification or accession, declare that it will not execute Letters of Request issued for the purpose of obtaining pre-trial discovery of documents as known in Common Law countries.
The table divides states into three categories: “Full exclusion” (no letters of request for pre-trial discovery of documents will be executed), “Qualified exclusion” (the state has indicated the circumstances in which it will or will not execute such a request), and “No declaration”.
The table also shows which states have made declarations excluding the operation of Chapter II of the Convention, which relates to taking of evidence by diplomatic officers, consular agents, or commissioners.