Doctrine of Intertemporal Law

The doctrine of intertemporal law requires historical state conduct to be assessed under the international law applicable when that conduct occurred, rather than automatically under present-day standards. It also distinguishes the creation of a legal right from its continued existence: maintaining a right may require compliance with the subsequent evolution of international law.

The two dimensions of the doctrine

The classic formulation appears in the Island of Palmas arbitration (1928), decided by Max Huber. It contains two connected but distinct propositions.

• The creation of a right must be assessed according to the law contemporary with the facts that allegedly created it.
• The continued existence of a right must satisfy the conditions required by the evolution of international law.
• Consequently, an entitlement validly acquired under an earlier legal order cannot simply be assumed to remain unaffected by later legal developments.

How historical state conduct should be assessed

The starting point is non-retroactivity: identifying a present-day prohibition does not, by itself, establish that the same prohibition governed conduct centuries earlier.

• The relevant inquiry identifies the conduct, its date or duration, and the treaty or customary rules binding the state at that time.
• Article 13 of the International Law Commission’s Articles on State Responsibility (2001) states that conduct does not breach an international obligation unless the state was bound by that obligation when the conduct occurred.
• Historical conduct must therefore be tested against contemporaneous obligations; its age neither automatically excuses it nor proves its unlawfulness.
• The doctrine does not freeze international law permanently at the historical starting point, especially where a claim concerns rights or conduct continuing into a later legal period.

Continuing wrongs and claims for reparation

A crucial distinction is between a continuing breach and the continuing effects of a completed act. Under Article 14 of the Articles on State Responsibility, an act without a continuing character does not become a continuing breach merely because its effects persist.

• Where wrongful conduct itself continues, the applicable obligations must be examined across the relevant period.
• A claim for reparation requires establishing a legally relevant breach attributable to the state and the resulting injury; intertemporal law supplies the temporal framework, not a complete answer to liability.
• Legal assessment under this doctrine is distinct from moral condemnation: present-day disapproval alone cannot replace proof of the applicable legal obligation.