His argument boils down to the statement that states can only violate international law if they adopt binding acts. Hence, as long as the Internal Market Bill is not adopted there could never be a breach. To the layman, this reasoning might seem plausible but it in fact goes against the very basics of public international law.

Here it just needs to be recalled that the ‘Articles on responsibility of states for internationally wrongful acts’, approved by the UN General Assembly in its Resolution 56/83 consistently refers to the wrongful conduct of states. Conduct can consist of acts or omissions and cannot be reduced to the simple adoption of binding law. The commentary to Article 12 explicitly notes that a breach “may involve the passage of legislation, or specific administrative or other action in a given case, or even a threat of such action, whether or not the threat is carried out.”

Barrett’s tautological assertion that “You only break international law if and when you break it” is beautifully simplistic but can likewise only convince the inadvertent layman. The question here precisely is whether by proposing the Bill, the UK government jeopardized the attainment of the objectives of the Withdrawal Agreement. As noted, a breach does not presuppose the adoption of binding law and a result the question cannot be dismissed by remarking that the Bill has not been adopted yet.

This is not to say that the UK has indeed breached its obligations. The Commission will have to show that bringing forward the Bill jeopardized the attainment of the Withdrawal Agreement’s objectives. If the case goes that far, it will ultimately be the Court of Justice of the EU deciding on this, since the UK sovereignly accepted the Court’s jurisdiction in Articles 86, 89 and 131 of the Withdrawal Agreement.