On February 8, 2023, the UK Supreme Court rejected [3] all three grounds of an appeal that challenged the constitutionality of the Northern Ireland Protocol [4]. Part of the post-Brexit agreement between the UK and EU, the protocol ensures that trade between the Republic of Ireland, an EU member, and Northern Ireland can continue without the need for checks after the UK left the EU. The protocol was established under British law by section 7A of the European (Withdrawal) Act of 2018 [5]. The appellants relied on three grounds. First, they argued that the protocol contradicts Article VI of the Acts of Union [6] of 1800 that unified and created the United Kingdom of Great Britain and Ireland. Second, they contended that Northern Ireland’s status cannot be substantially changed without poll procedures defined in Section 1(1) of the Northern Ireland Act of 1998 [7]. Finally, the appellants questioned the lawfulness of the protocol under the Protocol on Ireland/Northern Ireland (Democratic Consent Process) (EU Exit) Regulations 2020 [8]. All three grounds of appeal were dismissed by the Supreme Court.