The Holy Seerefuses to accept dual accreditation with Italy, an assertion of sovereignty dating from the prisoner-in-the-Vatican dispute.[2] For example, when Ireland closed its Holy See mission in Rome, accreditation as Irish ambassador to the Holy See was given to a diplomat based at the Department of Foreign Affairs in Dublin rather than to the Irish ambassador to Italy.[3]
According to the 2021 US State Department Office of Foreign Missions' Accreditation Handbook, "Separately, the Department may consider the dual accreditation of an individual performing administrative functions and duties only, e.g., a consular employee, who performs administrative duties or submits eGov transactions in connection with his/her government’s representation to the UN."[4]
See also
Protecting power, a third country representing the interests of a country in another country with which it does not have diplomatic relations