A dispute’s existence can be a requirement for establishing the jurisdiction of numerous international courts and tribunals. It requires that a state opposes the claim of another state. Yet, when a state is silent in response to a claim directed at it, there is ambiguity about the silent state’s view. This article argues that opposition and a dispute can be inferred from state silence under specific cumulative conditions: when a claim has been made in circumstances that call for the silent state’s reaction; when the silent state is aware of the claim; and when reasonable time of silence passed. Because it prevents tactical silences from undermining international justice, the inference must be encouraged. The conditions, under which the inference can be made, should also be retained in international adjudication, because they perform primarily an evidentiary function, as well as a cautionary and a channelling function.

This article challenges the widely held view that WTO Members are not permitted to impose trade restrictions on other WTO Members in the form of countermeasures for breaches of international law. It cautions that this generally held view has wider implications for international law and multilateralism because countermeasures are a significant means of enforcing and preserving the normative integrity of international obligations outside the WTO, including erga omnes and erga omnes partes obligations. Arguments supporting their ‘displacement’ must be based on clear evidence, which this article shows to be lacking. This article also attempts to allay the (understandable but perhaps exaggerated) concern that such countermeasures might undermine the predictability of the WTO system. Trade countermeasures for breaches of extra-WTO obligations are subject to stringent conditions under customary international law and to judicial scrutiny by means of WTO adjudication, both of which minimise the space for abuse and the risk of unpredictability.

The CJEU held that the United Kingdom of Great Britain and Northern Ireland (UK) is allowed to unilaterally revoke the notification of its intention to withdraw from the European Union (EU) as long as the revocation is submitted in writing to the European Council before the UK's withdrawal takes effect, and as long as the revocation is “unequivocal and unconditional, that is to say that the purpose of that revocation is to confirm the EU membership of the member state concerned under terms that are unchanged as regards its status as a member state, and that revocation brings the withdrawal procedure to an end” (para. 74).

The modern law of treaties applies regardless of whether a treaty is publicized. The secrecy of an international agreement does not affect its legal force, nonpublicized agreements may be used in interpreting a publicized treaty, and mere failure to comply with domestic requirements concerning publicity does not invalidate the treaty or a state's consent to be bound by it. Under the UN Charter, UN members may not invoke an unregistered treaty or international agreement before a UN organ, but the rules on state responsibility are not concerned with the secrecy or publicity of primary obligations. Injured states may resort to countermeasures for breaches of secret treaty obligations and can suspend compliance with secret treaty obligations as a countermeasure against the responsible state. States may also seek to enforce obligations in secret treaties by bringing claims in international courts and tribunals outside the UN system—and these courts and tribunals have proliferated.