Thread by @hmgillow

The statement in the Joint Political Declaration to the #WindsorFramework that "the Vienna Convention on the Law of Treaties ... applies to all international agreements including the Withdrawal
Agreement and its Protocol on Ireland / Northern Ireland" is very interesting.

The Vienna Convention applies to treaties between states (Art 1) and explicitly not treaties between states and international organisations (Art 3)

The ECJ has previously recognised that the Vienna Convention can apply insofar as it codifies principles of customary international law (e.g. Case C‑386/08 Brita GmbH at [40-41])

But unless I've missed something doesn't accept that the Vienna Convention applies to treaties between the EU and states

So @BillCashMP (per the PM's praise in the Commons today) has pulled off something of a coup in getting the EU to agree that the Vienna Convention applies not only to the Withdrawal Agreement / Windsor Framework, but to "all international agreements"

@BillCashMP Alternatively, as pointed out by one of my colleagues, is this the EU setting a precedent that its treaty making powers are, in effect, equivalent to a state? If so, an interesting move in circumstances where the UK is unlikely to object.