State immunity, once a doctrine of near-absolute character, has for some decades operated on a restrictive theory. The distinction between acts iure imperii and acts iure gestionis has become the standard analytical framework, and a substantial body of state practice and judicial decision has developed around it. The doctrine, in its restrictive form, is widely accepted in customary international law and is reflected in the United Nations Convention on Jurisdictional Immunities of States and Their Property.
The contemporary pressure on the doctrine arises less from the immunity from jurisdiction than from the immunity from execution. Even where a domestic court has properly exercised jurisdiction over a foreign state in respect of a commercial activity, the question of enforcement against state assets engages a separate and more restrictive set of principles. The categories of executable assets are narrow, the procedural requirements are demanding, and the practical result is that judgments against foreign states are difficult to enforce in this jurisdiction and in many others.
The South African position is articulated in the Foreign States Immunities Act, which broadly tracks the restrictive theory and which has been the subject of a developing body of decisions in the higher courts. The Act's treatment of execution is, however, sparser than its treatment of jurisdiction, and the courts have had to work out the operational rules through cases. The recent jurisprudence has tended towards a cautious application of the immunity from execution, with significant weight given to the public-law character of state assets even where the underlying transaction was commercial.
For practitioners advising in this area, the practical consequence is that the strategic considerations at the enforcement stage are at least as important as those at the jurisdictional stage. Identifying executable assets, structuring the claim to maximise the prospect of execution, and engaging with the relevant foreign relations dimensions of the proceeding are matters that need to be considered from the outset rather than at the point of judgment.