Article 5(f) of the Vienna Consular Convention authorizes consular officers to perform notarial and authentication functions in the countries to which they are posted. This means that certain consular officials at US embassies or consulates can provide the function of a US notary public abroad, including the administration of oaths and the witnessing of affidavits and attestations. This is helpful where no judicial assistance treaty is in effect and a foreign affidavit of service must be sworn abroad for use in a US court.
Article 5(f) of the Convention provides for the “authentication” or “legalization” of certain foreign seals and signatures by consular officials. A consular officer can thus attest to the validity of a foreign public document by inspecting its seal and placing a consular seal over the seal of the foreign authority. Consular officials authenticate hundreds of thousands of personal documents each year (birth certificates, divorce decrees, etc.) as well as documents produced in evidence which are to be filed in a US court.
Articles 5(f) and (j) of the Convention empower consular officers to administer oaths abroad to willing witnesses (generally pursuant to court order or commission) and/or otherwise assist in the taking of evidence abroad for US tribunals as long as this is not prohibited by the laws of the host (foreign) country.
Finally, Article 5(j) of the Convention provides that consular officials are to ensure the execution of letters rogatory seeking international judicial assistance on behalf of their domestic courts in any manner that is compatible with the laws and regulations of the country to which they are posted. This is the “diplomatic channel” by which US letters rogatory are transmitted from US courts to the courts of the host country for execution and evidence produced by foreign courts in response to letters of request are returned to the US.