In the case of Ohio ex rel. Popovici, Vice-Consul of Roumania v. Agler et al., 1929, the U.S Supreme Court ruled that a foreign diplomat could not claim exemption from state laws regarding marriage and divorce on grounds of diplomatic immunity. The petitioner was Mr. Popovici, who served as vice-consul for Romania in Cleveland, Ohio at the time and sought to prevent his wife's application for divorce by asserting his diplomatic status which he believed exempted him from local jurisdiction over personal matters such as marital disputes. However, after reviewing international law principles and past precedents concerning consular privileges and immunities under U.S law, the court concluded that while diplomats enjoy certain protections against criminal prosecution or civil lawsuits related to their official duties; they are still subject to domestic laws governing private affairs including family relations unless explicitly stated otherwise in treaties or statutes.

In the dissenting opinion for Ohio ex rel. Popovici, Vice-Consul of Roumania v. Agler et al., Justice Oliver Wendell Holmes argued that diplomatic immunity should extend to consular officials like Mr. Popovici as well as ambassadors and ministers plenipotentiary. He contended that the majority's decision was based on an overly narrow interpretation of international law and historical precedent, which he believed clearly supported a broader understanding of diplomatic immunity protections. Furthermore, he expressed concern about the potential implications this ruling could have on U.S diplomats serving abroad who might be subjected to similar legal actions in foreign courts if other countries decided to reciprocate with similarly restrictive interpretations of diplomatic immunity rights.