In the 1942 case Ex parte Republic of Peru, the U.S. Supreme Court ruled in favor of Peru's claim to sovereign immunity. The dispute began when a Peruvian vessel was seized by an American company for unpaid debts while docked at a port in California. The Republic of Peru filed for its release on grounds that it was immune from such actions due to its status as a foreign sovereign nation under international law. Lower courts denied this request, leading to an appeal before the Supreme Court. The court reversed these decisions and held that the seizure violated principles of international comity and respect among nations, which grant immunity from jurisdictional suits to foreign states unless they consent otherwise or there is statutory authorization permitting such suits. This decision reinforced traditional notions of state sovereignty and non-interference in domestic affairs by other states.

In the dissenting opinion for Ex parte Republic of Peru, Justice Frank Murphy argued that the majority's decision to allow U.S. courts jurisdiction over a foreign government-owned vessel was an overreach and could potentially harm international relations. He contended that such matters should be left to diplomatic channels rather than judicial intervention. Murphy emphasized respect for sovereign immunity, arguing it is not within the court’s purview to decide whether or not this principle applies; instead, he believed it should be determined by political branches of government due to its potential impact on foreign policy. Furthermore, he expressed concern about reciprocity - if U.S courts can exercise jurisdiction in such cases involving foreign governments' property, then American governmental property abroad might also become subject to local jurisdictions.